CTAN sync 202406030302

75 files changed, 2347 insertions, 256 deletions

diff --git a/macros/latex/required/tools/README.md b/macros/latex/required/tools/README.md
index f08c378fff..6413c06b37 100644
--- a/macros/latex/required/tools/README.md
+++ b/macros/latex/required/tools/README.md
@@ -1,7 +1,7 @@
 The LaTeX `tools` bundle
 ========================
 
-Release 2023-11-01c
+Release 2024-06-01 patch level 0
 
 Overview
 --------
diff --git a/macros/latex/required/tools/afterpage.dtx b/macros/latex/required/tools/afterpage.dtx
index 518b70761d..72df39402c 100644
--- a/macros/latex/required/tools/afterpage.dtx
+++ b/macros/latex/required/tools/afterpage.dtx
@@ -1,6 +1,6 @@
 % \iffalse meta-comment
 %
-% Copyright (C) 1993-2023
+% Copyright (C) 1993-2024
 %
 % The LaTeX Project and any individual authors listed elsewhere
 % in this file.
diff --git a/macros/latex/required/tools/afterpage.ins b/macros/latex/required/tools/afterpage.ins
index 6fec5edc6f..17792ddfa1 100644
--- a/macros/latex/required/tools/afterpage.ins
+++ b/macros/latex/required/tools/afterpage.ins
@@ -3,7 +3,7 @@
 %% driver files from the doc files in this package when run through
 %% LaTeX or TeX.
 %%
-%% Copyright (C) 1993-2023
+%% Copyright (C) 1993-2024
 %% The LaTeX Project and any individual authors listed elsewhere
 %% in this file.
 %%
@@ -45,7 +45,7 @@ The source is maintained by the LaTeX Project team and bug
 reports for it can be opened at https://latex-project.org/bugs/
 (but please observe conditions on bug reports sent to that address!)
 
-Copyright (C) 1993-2023
+Copyright (C) 1993-2024
 The LaTeX Project and any individual authors listed elsewhere
 in this file.
 
diff --git a/macros/latex/required/tools/afterpage.pdf b/macros/latex/required/tools/afterpage.pdf
index 3782fae988..ef7a17844e 100644
--- a/macros/latex/required/tools/afterpage.pdf
+++ b/macros/latex/required/tools/afterpage.pdf
diff --git a/macros/latex/required/tools/array-2016-10-06.sty b/macros/latex/required/tools/array-2016-10-06.sty
index f079fd4975..ced72d2913 100644
--- a/macros/latex/required/tools/array-2016-10-06.sty
+++ b/macros/latex/required/tools/array-2016-10-06.sty
@@ -1,5 +1,7 @@
 %%
-%% This is an old release of `array.sty',
+%% This is an old release of `array.sty' used during rollback operations.
+%% Do not use this file directly.
+%% ==============================
 %%
 %% Copyright 1993-2016
 %% The LaTeX Project and any individual authors listed elsewhere
diff --git a/macros/latex/required/tools/array-2020-02-10.sty b/macros/latex/required/tools/array-2020-02-10.sty
index 1243f25f74..5acd9c727e 100644
--- a/macros/latex/required/tools/array-2020-02-10.sty
+++ b/macros/latex/required/tools/array-2020-02-10.sty
@@ -1,4 +1,8 @@
 %%
+%% This is an old release of `array.sty' used during rollback operations.
+%% Do not use this file directly.
+%% ==============================
+%%
 %% This is file `array.sty',
 %% generated with the docstrip utility.
 %%
@@ -38,11 +42,6 @@
 %% Package `array' to use with LaTeX 2e
 %% Copyright (C) 1989-1998 Frank Mittelbach, all rights reserved.
 \NeedsTeXFormat{LaTeX2e}[1995/06/01]
-\providecommand\DeclareRelease[3]{}
-\providecommand\DeclareCurrentRelease[2]{}
-
-\DeclareRelease{}{2016-10-06}{array-2016-10-06.sty}
-\DeclareCurrentRelease{}{2019-10-01}
 
 \ProvidesPackage{array}
          [2020/02/10 v2.4m Tabular extension package (FMi)]
diff --git a/macros/latex/required/tools/array-2023-11-01.sty b/macros/latex/required/tools/array-2023-11-01.sty
new file mode 100644
index 0000000000..b5267cffd2
--- /dev/null
+++ b/macros/latex/required/tools/array-2023-11-01.sty
@@ -0,0 +1,373 @@
+%%
+%% This is an old release of `array.sty' used during rollback operations.
+%% Do not use this file directly.
+%% ==============================
+%%
+%% This is file `array.sty',
+%% generated with the docstrip utility.
+%%
+%% The original source files were:
+%%
+%% array.dtx  (with options: `package,ncols')
+%% 
+%% This is a generated file.
+%% 
+%% The source is maintained by the LaTeX Project team and bug
+%% reports for it can be opened at https://latex-project.org/bugs/
+%% (but please observe conditions on bug reports sent to that address!)
+%% 
+%% 
+%% Copyright (C) 1993-2023
+%% The LaTeX Project and any individual authors listed elsewhere
+%% in this file.
+%% 
+%% This file was generated from file(s) of the Standard LaTeX `Tools Bundle'.
+%% --------------------------------------------------------------------------
+%% 
+%% It may be distributed and/or modified under the
+%% conditions of the LaTeX Project Public License, either version 1.3c
+%% of this license or (at your option) any later version.
+%% The latest version of this license is in
+%%    https://www.latex-project.org/lppl.txt
+%% and version 1.3c or later is part of all distributions of LaTeX
+%% version 2005/12/01 or later.
+%% 
+%% This file may only be distributed together with a copy of the LaTeX
+%% `Tools Bundle'. You may however distribute the LaTeX `Tools Bundle'
+%% without such generated files.
+%% 
+%% The list of all files belonging to the LaTeX `Tools Bundle' is
+%% given in the file `manifest.txt'.
+%% 
+%% Package `array' to use with LaTeX 2e
+%% Copyright (C) 1989-1998 Frank Mittelbach, all rights reserved.
+\NeedsTeXFormat{LaTeX2e}[1995/06/01]
+
+\ProvidesPackage{array}
+         [2023/10/16 v2.5g Tabular extension package (FMi)]
+%%
+
+\def\@addtopreamble#1{\xdef\@preamble{\@preamble #1}}
+\def\@testpach{\@chclass
+ \ifnum \@lastchclass=6 \@ne \@chnum \@ne \else
+  \ifnum \@lastchclass=7 5 \else
+   \ifnum \@lastchclass=8 \tw@ \else
+    \ifnum \@lastchclass=9 \thr@@
+   \else \z@
+   \ifnum \@lastchclass = 10 \else
+   \edef\@nextchar{\expandafter\string\@nextchar}%
+   \@chnum
+   \if \@nextchar c\z@ \else
+    \if \@nextchar l\@ne \else
+     \if \@nextchar r\tw@ \else
+   \z@ \@chclass
+   \if\@nextchar |\@ne \else
+    \if \@nextchar !6 \else
+     \if \@nextchar @7 \else
+      \if \@nextchar <8 \else
+       \if \@nextchar >9 \else
+  10
+  \@chnum
+  \if \@nextchar m\thr@@\else
+   \if \@nextchar p4 \else
+    \if \@nextchar b5 \else
+   \z@ \@chclass \z@ \@preamerr \z@ \fi \fi \fi \fi
+   \fi \fi  \fi  \fi  \fi  \fi  \fi \fi \fi \fi \fi \fi}
+\def\@xexpast#1*#2#3#4\@@{%
+   \@tempcnta #2
+   \toks@={#1}\@temptokena={#3}%
+   \let\the@toksz\relax \let\the@toks\relax
+   \def\@tempa{\the@toksz}%
+   \ifnum\@tempcnta >0 \@whilenum\@tempcnta >0\do
+     {\edef\@tempa{\@tempa\the@toks}\advance \@tempcnta \m@ne}%
+       \let \@tempb \@xexpast \else
+       \let \@tempb \@xexnoop \fi
+   \def\the@toksz{\the\toks@}\def\the@toks{\the\@temptokena}%
+   \edef\@tempa{\@tempa}%
+   \expandafter \@tempb \@tempa #4\@@}
+\def\prepnext@tok{\advance \count@ \@ne
+   \toks\count@{}}
+\def\save@decl{\toks\count@ \expandafter{\@nextchar}}
+\def\insert@column{%
+   \the@toks \the \@tempcnta
+   \ignorespaces \@sharp \unskip
+   \the@toks \the \count@ \relax}
+\newdimen\col@sep
+\def\@acol{\@addtopreamble{\hskip\col@sep}}
+\def\@classx{%
+  \ifcase \@lastchclass
+  \@acolampacol \or
+  \@addamp \@acol \or
+  \@acolampacol \or
+  \or
+  \@acol \@firstampfalse \or
+  \@addamp
+  \fi}
+\def\@classz{\@classx
+   \@tempcnta \count@
+   \prepnext@tok
+   \@addtopreamble{\ifcase \@chnum
+      \hfil
+      \hskip1sp%
+      \d@llarbegin
+      \insert@column
+      \d@llarend \do@row@strut \hfil \or
+      \hskip1sp\d@llarbegin \insert@column \d@llarend \do@row@strut \hfil \or
+      \hfil\hskip1sp\d@llarbegin \insert@column \d@llarend \do@row@strut \or
+    \setbox\ar@mcellbox\vbox
+    \@startpbox{\@nextchar}\insert@column \@endpbox
+    \ar@align@mcell
+    \do@row@strut \or
+   \vtop \@startpbox{\@nextchar}\insert@column \@endpbox\do@row@strut \or
+   \vbox \@startpbox{\@nextchar}\insert@column \@endpbox\do@row@strut
+  \fi}\prepnext@tok}
+
+\newbox\ar@mcellbox
+\def\ar@align@mcell{%
+  \ifdim \ht\ar@mcellbox > \ht\strutbox
+    \begingroup
+     \dimen@\ht\ar@mcellbox
+     \advance\dimen@-\ht\@arstrutbox
+     \advance\dimen@\baselineskip
+     \lower.5\dimen@\box\ar@mcellbox
+    \endgroup
+  \else % assume one line and align at baseline
+    \box\ar@mcellbox
+  \fi}
+
+\def\@arrayrule{\@addtopreamble \vline}
+\def\@classvii{\ifnum \@lastchclass = \thr@@
+   \@preamerr \thr@@ \fi}
+\def\@classvi{\ifcase \@lastchclass
+      \@acol \or
+      \@addtopreamble{\hskip \doublerulesep}\or
+      \@acol \or
+      \@classvii
+      \fi}
+\def\@classii{\advance \count@ \m@ne
+   \save@decl\prepnext@tok}
+\def\@classi{\@classvi
+   \ifcase \@chnum \@arrayrule \or
+      \@classv \fi}
+\def\@startpbox#1{\bgroup
+  \color@begingroup
+  \setlength\hsize{#1}\@arrayparboxrestore
+   \everypar{%
+      \vrule \@height \ht\@arstrutbox \@width \z@
+      \everypar{}}%
+   }
+\def\@endpbox{\@finalstrut\@arstrutbox \par \color@endgroup \egroup\hfil}
+\def\@array[#1]#2{%
+  \@tempdima \ht \strutbox
+  \advance \@tempdima by\extrarowheight
+  \setbox \@arstrutbox \hbox{\vrule
+             \@height \arraystretch \@tempdima
+             \@depth \arraystretch \dp \strutbox
+             \@width \z@}%
+  \begingroup
+  \@mkpream{#2}%
+  \xdef\@preamble{\noexpand \ialign \@halignto
+                  \bgroup \@arstrut \@preamble
+                          \tabskip \z@ \cr}%
+  \endgroup
+  \@arrayleft
+  \if #1t\vtop \else \if#1b\vbox \else \vcenter \fi \fi
+  \bgroup
+  \let \@sharp ##\let \protect \relax
+  \lineskip \z@
+  \baselineskip \z@
+  \m@th
+  \let\\\@arraycr \let\tabularnewline\\\let\par\@empty \@preamble}
+\def\arraybackslash{\let\\\tabularnewline}
+\newdimen \extrarowheight
+\extrarowheight=0pt
+\def\@arstrut{\unhcopy\@arstrutbox}
+\protected\def\@arraycr{\relax\iffalse{\fi\ifnum 0=`}\fi
+  \@ifstar \@xarraycr \@xarraycr}
+\def\@xarraycr{\@ifnextchar [%
+  \@argarraycr {\ifnum 0=`{}\fi\cr}}
+\def\@argarraycr[#1]{\ifnum0=`{}\fi\ifdim #1>\z@
+  \expandafter\@xargarraycr\else
+  \expandafter\@yargarraycr\fi{#1}}
+\def\@xargarraycr#1{\unskip\gdef\do@row@strut
+ {\@tempdima #1\advance\@tempdima \dp\@arstrutbox
+   \vrule \@depth\@tempdima \@width\z@\global\let\do@row@strut\relax}%
+   \ifnum\@multicnt >\z@ \do@row@strut \fi
+   \cr}
+\let\do@row@strut\relax
+\long\def\multicolumn#1#2#3{%
+   \multispan{#1}\begingroup
+   \def\@addamp{\if@firstamp \@firstampfalse \else
+                \@preamerr 5\fi}%
+   \@mkpream{#2}\@addtopreamble\@empty
+   \endgroup
+   \def\@sharp{#3}%
+   \@arstrut \@preamble
+   \null
+   \ignorespaces}
+\let\d@llarbegin\begingroup
+\let\d@llarend\endgroup
+\def\array{\col@sep\arraycolsep
+  \def\d@llarbegin{$}\let\d@llarend\d@llarbegin\def\@halignto{}%
+  \@tabarray}
+\def\tabular{\def\@halignto{}\@tabular}
+\expandafter\def\csname tabular*\endcsname#1{%
+       \setlength\dimen@{#1}%
+       \edef\@halignto{to\the\dimen@}\@tabular}
+\def\@tabular{%
+  \leavevmode
+  \hbox \bgroup $\col@sep\tabcolsep \let\d@llarbegin\begingroup
+                                    \let\d@llarend\endgroup
+  \@tabarray}
+\def\endtabular{\endarray\m@th $\egroup}
+\expandafter\let\csname endtabular*\endcsname=\endtabular
+\let\@ampacol=\relax        \let\@expast=\relax
+\let\@arrayclassiv=\relax   \let\@arrayclassz=\relax
+\let\@tabclassiv=\relax     \let\@tabclassz=\relax
+\let\@arrayacol=\relax      \let\@tabacol=\relax
+\let\@tabularcr=\relax      \let\@@endpbox=\relax
+\let\@argtabularcr=\relax   \let\@xtabularcr=\relax
+\def\@preamerr#1{\def\@tempd{{..} at wrong position: }%
+   \PackageError{array}{%
+   \ifcase #1 Illegal pream-token (\@nextchar): `c' used\or %0
+    Missing arg: token ignored\or                           %1
+    Empty preamble: `l' used\or                             %2
+    >\@tempd token ignored\or                               %3
+    <\@tempd changed to !{..}\or                            %4
+    Only one column-spec. allowed.\fi}\@ehc}                %5
+\def\newcolumntype#1{%
+  \edef\NC@char{\string#1}%
+  \@ifundefined{NC@find@\NC@char}%
+    {\@tfor\next:=<>clrmbp@!|\do
+      {%
+        \if\expandafter\noexpand\next\NC@char
+        \PackageWarning{array}%
+                       {Redefining primitive column \NC@char}\fi}%
+     \NC@list\expandafter{\the\NC@list\NC@do#1}}%
+    {\PackageWarning{array}{Column \NC@char\space is already defined}}%
+  \@namedef{NC@find@\NC@char}##1#1{\NC@{##1}}%
+  \@ifnextchar[{\newcol@{\NC@char}}{\newcol@{\NC@char}[0]}}
+\def\newcol@#1[#2]#3{\expandafter\@reargdef
+     \csname NC@rewrite@#1\endcsname[#2]{\NC@find#3}}
+\def\NC@#1{%
+  \@temptokena\expandafter{\the\@temptokena#1}\futurelet\next\NC@ifend}
+\def\NC@ifend{%
+  \ifx\next\relax
+    \else\@tempswatrue\expandafter\NC@rewrite\fi}
+\def\NC@do#1{%
+  \expandafter\let\expandafter\NC@rewrite
+    \csname NC@rewrite@\string#1\endcsname
+  \expandafter\let\expandafter\NC@find
+    \csname NC@find@\string#1\endcsname
+  \expandafter\@temptokena\expandafter{\expandafter}%
+        \expandafter\NC@find\the\@temptokena#1\relax}
+\def\showcols{{\def\NC@do##1{\let\NC@do\NC@show}\the\NC@list}}
+\def\NC@show#1{%
+  \typeout{Column #1\expandafter\expandafter\expandafter\NC@strip
+  \expandafter\meaning\csname NC@rewrite@#1\endcsname\@@}}
+\def\NC@strip#1:#2->#3 #4\@@{#2 -> #4}
+\newtoks\NC@list
+\newcolumntype{*}[2]{}
+\long\@namedef{NC@rewrite@*}#1#2{%
+  \count@#1\relax
+  \loop
+  \ifnum\count@>\z@
+  \advance\count@\m@ne
+  \@temptokena\expandafter{\the\@temptokena#2}%
+  \repeat
+  \NC@find}
+\let\@xexpast\relax
+\let\@xexnoop\relax
+\def\save@decl{\toks \count@ = \expandafter\expandafter\expandafter
+                  {\expandafter\@nextchar\the\toks\count@}}
+\def\@mkpream#1{\gdef\@preamble{}\@lastchclass 4 \@firstamptrue
+   \let\@sharp\relax
+   \def\@startpbox##1{\unexpanded\expandafter{\expandafter
+                      \@startpbox\expandafter{##1}}}\let\@endpbox\relax
+   \let\do@row@strut\relax
+   \let\ar@align@mcell\relax
+   \@temptokena{#1}\@tempswatrue
+   \@whilesw\if@tempswa\fi{\@tempswafalse\the\NC@list}%
+   \count@\m@ne
+   \let\the@toks\relax
+   \prepnext@tok
+   \expandafter \@tfor \expandafter \@nextchar
+    \expandafter :\expandafter =\the\@temptokena \do
+   {\@testpach
+   \ifcase \@chclass \@classz \or \@classi \or \@classii
+     \or \save@decl \or \or \@classv \or \@classvi
+     \or \@classvii \or \@classviii
+     \or \@classx
+     \or \@classx \fi
+   \@lastchclass\@chclass}%
+   \ifcase\@lastchclass
+   \@acol \or
+   \or
+   \@acol \or
+   \@preamerr \thr@@ \or
+   \@preamerr \tw@ \@addtopreamble\@sharp \or
+   \or
+   \else  \@preamerr \@ne \fi
+   \def\the@toks{\the\toks}}
+\let\@classix\relax
+\def\@classviii{\ifnum \@lastchclass >\z@\ifnum\@lastchclass=\tw@\else
+      \@preamerr 4\@chclass 6 \@classvi \fi\fi}
+\def\@classv{\save@decl
+   \expandafter\NC@ecs\@nextchar\extracolsep{}\extracolsep\@@@
+   \@addtopreamble{\d@llarbegin\the@toks\the\count@\relax\d@llarend}%
+   \prepnext@tok}
+\def\NC@ecs#1\extracolsep#2#3\extracolsep#4\@@@{\def\@tempa{#2}%
+  \ifx\@tempa\@empty\else\toks\count@={#1\tabskip#2\relax#3}\fi}
+\def\@tabarray{\@ifnextchar[{\@@array}{\@@array[c]}}
+\let\@@array\@array
+\def\endarray{\crcr \egroup \egroup \@arrayright \gdef\@preamble{}}
+\let\@arrayleft\@empty
+\let\@arrayright\@empty
+\newlength{\extratabsurround}
+\setlength{\extratabsurround}{2pt}
+\newlength{\backup@length}
+\newcommand{\firsthline}{%
+  \multicolumn1{@{}c@{}}{%
+    \global\backup@length\ht\@arstrutbox
+    \global\advance\backup@length\dp\@arstrutbox
+    \global\advance\backup@length\arrayrulewidth
+     \raise\extratabsurround\copy\@arstrutbox
+     \kern-1sp%
+    }\\[-\backup@length]\hline
+}
+\newcommand{\lasthline}{\hline\multicolumn1{@{}c@{}}{%
+    \global\backup@length2\ht\@arstrutbox
+    \global\advance\backup@length2\dp\@arstrutbox
+    \global\advance\backup@length\arrayrulewidth
+    }\\[-\backup@length]%
+    \multicolumn1{@{}c@{}}{%
+       \lower\extratabsurround\copy\@arstrutbox
+       \kern-1sp%
+       }%
+}
+\CheckCommand*\@xhline{\ifx\reserved@a\hline
+               \vskip\doublerulesep
+               \vskip-\arrayrulewidth
+             \fi
+      \ifnum0=`{\fi}}
+\renewcommand*\@xhline{\ifx\reserved@a\hline
+               \vskip\doublerulesep
+             \fi
+      \ifnum0=`{\fi}}
+
+\newsavebox\ar@cellbox
+\newcolumntype{w}[2]{%
+  >{\begin{lrbox}\ar@cellbox\d@llarbegin}%
+  c%
+  <{\d@llarend \end{lrbox}%
+    \makebox[#2][#1]{\unhbox\ar@cellbox}}}
+
+\newcolumntype{W}[2]
+  {>{\begin{lrbox}\ar@cellbox\d@llarbegin}%
+   c%
+   <{\d@llarend\end{lrbox}%
+   \let\hss\hfil
+   \makebox[#2][#1]{\unhbox\ar@cellbox}}}
+\endinput
+%%
+%% End of file `array.sty'.
diff --git a/macros/latex/required/tools/array.dtx b/macros/latex/required/tools/array.dtx
index 6e4e34ea26..e77ef0a3bf 100644
--- a/macros/latex/required/tools/array.dtx
+++ b/macros/latex/required/tools/array.dtx
@@ -1,6 +1,6 @@
 % \iffalse meta-comment
 %
-% Copyright (C) 1993-2023
+% Copyright (C) 1993-2024
 %
 % The LaTeX Project and any individual authors listed elsewhere
 % in this file.
@@ -25,15 +25,21 @@
 %% Package `array' to use with LaTeX 2e
 %% Copyright (C) 1989-1998 Frank Mittelbach, all rights reserved.
 %<+package>\NeedsTeXFormat{LaTeX2e}[1995/06/01]
-%<+package>\providecommand\DeclareRelease[3]{}
-%<+package>\providecommand\DeclareCurrentRelease[2]{}
 %<+package>
+% For anything before 2016-10-06 we load the 2016 version and hope for the best:
+%<+package>\DeclareRelease{}{1994-06-01}{array-2016-10-06.sty}
+%
 %<+package>\DeclareRelease{}{2016-10-06}{array-2016-10-06.sty}
 %<+package>\DeclareRelease{v2.4}{2020-02-10}{array-2020-02-10.sty}
-%<+package>\DeclareCurrentRelease{}{2020-10-01}
+%<+package>\DeclareRelease{v2.5}{2023-11-01}{array-2023-11-01.sty}
+%<+package>\DeclareCurrentRelease{}{2024-06-01}
 %<+package>
+%    \end{macrocode}
+%    Current version needs a new kernel.
+%    \begin{macrocode}
+%<+package>\NeedsTeXFormat{LaTeX2e}[2024/06/01]
 %<+package>\ProvidesPackage{array}
-%<+package>         [2023/10/16 v2.5g Tabular extension package (FMi)]
+%<+package>         [2024/05/23 v2.6c Tabular extension package (FMi)]
 %
 % \fi
 %
@@ -177,6 +183,18 @@
 % \DoNotIndex{\xdef}
 % \DoNotIndex{\z@}
 %
+%
+% \providecommand\env[1]{\texttt{#1}}
+%
+% \providecommand\hook[1]{\texttt{#1\DescribeHook[noprint]{#1}}}
+% \providecommand\socket[1]{\texttt{#1\DescribeSocket[noprint]{#1}}}
+% \providecommand\plug[1]{\texttt{#1\DescribePlug[noprint]{#1}}}
+%
+% \NewDocElement[printtype=\textit{socket},idxtype=socket,idxgroup=Sockets]{Socket}{socketdecl}
+% \NewDocElement[printtype=\textit{hook},idxtype=hook,idxgroup=Hooks]{Hook}{hookdecl}
+% \NewDocElement[printtype=\textit{plug},idxtype=plug,idxgroup=Plugs]{Plug}{plugdecl}
+%
+%
 % \GetFileInfo{array.sty}
 %
 % \title{A new implementation of \LaTeX's \textsf{tabular}
@@ -195,6 +213,8 @@
 % \MaintainedByLaTeXTeam{tools}
 % \maketitle
 %
+%
+%
 % \MakeShortVerb{\=}
 %
 % \begin{abstract}
@@ -750,12 +770,29 @@
 % \end{itemize}
 %
 %
+% \section{Support for tagged PDF}
 %
-% \changes{v2.2b}{1994/02/04}{Removed interactive prompt}
+% With version 2.6a the package is made tagging aware, which means that
+% it will automatically produce tagged tables (necessary, for example, for
+% accessibility) if tagging is requested via \cs{DocumentMetadata}.
 %
-% \MaybeStop{
+% More granular control, e.g., explicitly deciding which cells are
+% header cells, etc., is currently under development, but syntax for
+% this will not appear in this package. Instead it will become
+% available across all tabular-generating packages and then
+% automatically apply here as well.
+%
+% Enabling \LaTeX{} to automatically produce tagged PDF is a long-term
+% project and this is a tiny step in this puzzle. For more information
+% on the project and already available functionality, see
+% \url{https://latex-project.org/publications/indexbytopic/pdf} and
+% \url{https://github.com/latex3/tagging-project}.
 %
 %
+%
+% \changes{v2.2b}{1994/02/04}{Removed interactive prompt}
+%
+% \MaybeStop{
 % \begin{thebibliography}{1}
 %    \bibitem{bk:GMS94} \textsc{M.~Goossens}, \textsc{F.~Mittelbach}
 %       and \textsc{A.~Samarin}.
@@ -772,7 +809,6 @@
 %       \newblock
 %       Addison-Wesley, Reading, Massachusetts, 1986.
 % \end{thebibliography}
-%
 % }   ^^A  end of \MaybeStop
 %
 %
@@ -786,8 +822,49 @@
 % \texttt{docstrip} program.
 %    \begin{macrocode}
 %<*driver>
-\NeedsTeXFormat{LaTeX2e}[1995/12/01]
-\documentclass{ltxdoc}
+\NeedsTeXFormat{LaTeX2e}[2024/06/01]
+%    \end{macrocode}
+%
+%    We switched from \cls{ltxdoc} to \cls{l3doc} to get support for
+%    code written in the L3 programming layer. The first is that we
+%    are currently missing \cs{MaintainedByLaTeXTeam}, so we have to
+%    provide that for now. 
+%    \begin{macrocode}
+\documentclass{l3doc}
+
+% currently missing in l3doc
+\makeatletter
+\def\MaintainedBy#1{\gdef\@maintainedby{#1}}
+\let\@maintainedby\@empty
+\def\MaintainedByLaTeXTeam#1{%
+{\gdef\@maintainedby{%
+This file is maintained by the \LaTeX{} Project team.\\%
+Bug reports can be opened (category \texttt{#1}) at\\%
+\url{https://latex-project.org/bugs.html}.}}}
+\def\@maketitle{%
+  \newpage
+  \null
+  \vskip 2em%
+  \begin{center}%
+  \let \footnote \thanks
+    {\LARGE \@title \par}%
+    \vskip 1.5em%
+    {\large
+      \lineskip .5em%
+      \begin{tabular}[t]{c}%
+        \@author
+      \end{tabular}\par}%
+    \vskip 1em%
+    {\large \@date}%
+    \ifx\@maintainedby\@empty
+    \else
+    \vskip 1em%
+    \fbox{\fbox{\begin{tabular}{@{}l@{}}\@maintainedby\end{tabular}}}%
+    \fi
+  \end{center}%
+  \par
+  \vskip 1.5em}
+\makeatother
 
 % undo the default is not used:
 
@@ -817,6 +894,29 @@
 %    \end{macrocode}
 %
 %
+% \section{A note on the updates done December 2023}
+%
+% We introduced support for tagged PDf and at the same time we added
+% code to determine row and column numbers for each cell in
+% preparation for supporting  formatting or type specifications for individual
+% cells (or group of cells) from the outside, e.g., \enquote{rows 1,
+% 2, and 10 are header rows} (syntax to be decided).
+%
+% This new code is already written with L3 programming layer conventions
+% while most of the legay code is still as it was before. This make the code
+% currently somewhat clattered, unfortunately. Eventually this will all move to L3
+% programming layer but this will take time.
+%
+%
+%    \begin{macrocode}
+%<@@=tbl>
+\ExplSyntaxOn
+%    \end{macrocode}
+%
+%
+%
+%
+%
 % \section{The construction of the preamble}
 %
 % \DeleteShortVerb{\"}
@@ -972,6 +1072,7 @@
 %    =\@chclass= and =\@chnum=.
 % \changes{v2.0f}{1992/02/29}{Argument removed since implicitly known}
 %    \begin{macrocode}
+\ExplSyntaxOff
 \def\@testpach{\@chclass
 %    \end{macrocode}
 %    First we deal with the cases in which the \textsf{token}
@@ -981,7 +1082,7 @@
  \ifnum \@lastchclass=6 \@ne \@chnum \@ne \else
   \ifnum \@lastchclass=7 5 \else
    \ifnum \@lastchclass=8 \tw@ \else
-    \ifnum \@lastchclass=9 \thr@@
+    \ifnum \@lastchclass=9 \thr@@@@
 %    \end{macrocode}
 %    Otherwise we will assume that the \textsf{token} belongs to the
 %    class $0$
@@ -1032,7 +1133,7 @@
 %    \begin{macrocode}
   10
   \@chnum
-  \if \@nextchar m\thr@@\else
+  \if \@nextchar m\thr@@@@ \else
    \if \@nextchar p4 \else
     \if \@nextchar b5 \else
 %    \end{macrocode}
@@ -1042,6 +1143,7 @@
 %    \begin{macrocode}
    \z@ \@chclass \z@ \@preamerr \z@ \fi \fi \fi \fi
    \fi \fi  \fi  \fi  \fi  \fi  \fi \fi \fi \fi \fi \fi}
+\ExplSyntaxOn
 %    \end{macrocode}
 % \end{macro}
 %
@@ -1062,10 +1164,10 @@
 %    they are in explicit braces, as in =@{*}=.
 %
 %    This macro is called via
-%    =\@xexpast=\meta{preamble}=*0x\@@=.
+%    =\@xexpast=\meta{preamble}=*0x\@@@@=.
 %    The $*$--expression =*0x= is being used to terminate the
 %    recursion,
-%    as we shall see later, and =\@@= serves as an argument
+%    as we shall see later, and =\@@@@= serves as an argument
 %    delimiter. =\@xexpast= has four arguments. The first
 %    one is the part of the
 %    user preamble before the first $*$--expression while the second
@@ -1074,7 +1176,7 @@
 %    above).
 %    The fourth argument is the rest of the preamble.
 %    \begin{macrocode}
-\def\@xexpast#1*#2#3#4\@@{%
+\def\@xexpast#1*#2#3#4\@@@@{%
 %    \end{macrocode}
 %    The number of copies of \textit{String} (=#2=) that are to be
 %    produced will be saved in a \textsf{count} register.
@@ -1111,7 +1213,7 @@
 %    \end{macrocode}
 %    If \textit{N\/} was greater than zero we prepare for another call
 %    of =\@xexpast=. Otherwise we assume we have reached the end of
-%    the user preamble, because we had appended =*0x\@@= when we first
+%    the user preamble, because we had appended =*0x\@@@@= when we first
 %    called =\@xexpast=.  In other words: if the user inserts
 %    =*{0}{..}= in his preamble, \LaTeX\ ignores the rest of it.
 %    \begin{macrocode}
@@ -1133,7 +1235,7 @@
 %    $*$--expression is handled, or to the macro =\@xexnoop=,
 %    which only ends the recursion by deleting its argument.
 %    \begin{macrocode}
-   \expandafter \@tempb \@tempa #4\@@}
+   \expandafter \@tempb \@tempa #4\@@@@}
 %    \end{macrocode}
 % \end{macro}
 % \end{macro}
@@ -1142,10 +1244,10 @@
 % \begin{macro}{\@xexnoop}
 %    So the first big problem is solved. Now it is easy to
 %    specify =\@xexnoop=.
-%    Its argument is delimited by =\@@= and it simply expands to
+%    Its argument is delimited by =\@@@@= and it simply expands to
 %    nothing.
 %    \begin{macrocode}
-%  \def\@xexnoop#1\@@{}
+%  \def\@xexnoop#1\@@@@{}
 %    \end{macrocode}
 % \end{macro}
 %
@@ -1270,11 +1372,19 @@
 %
 % \begin{macro}{\insert@column}
 % \begin{macro}{\@sharp}
+% \begin{macro}{\textonly@unskip}
 %    We now define the macro =\insert@column= which will do
 %    this work for us.
 %    \begin{macrocode}
 \def\insert@column{%
 %    \end{macrocode}
+%
+%    For tagging we insert as special socket, that adds the necessary
+%    PDF tag at the beginning of the cell if tagging is enabled.
+% \changes{v2.6a}{2023/12/11}{Support for tagged PDF}
+%    \begin{macrocode}
+  \UseTaggingSocket{tbl/cell/begin}%
+%    \end{macrocode}
 %    Here, we assume that the \textsf{count} register
 %    =\@tempcnta= has saved the value $=\count@= - 1$.
 %    \begin{macrocode}
@@ -1291,8 +1401,9 @@
 % \changes{v2.0e}{1991/02/07}{Added \{\} around \cs{@sharp} for new ftsel}
 % \changes{v2.0h}{1992/06/22}{Removed \{\} again in favour of
 %                             \cs{d@llarbegin}}
+% \changes{v2.6b}{2024/04/08}{Do not \cs{unskip} if in math mode (gh/1323)}
 %    \begin{macrocode}
-   \ignorespaces \@sharp \unskip
+   \ignorespaces \@sharp \textonly@unskip
 %    \end{macrocode}
 %    Then the second \textsf{token} register follows whose number should
 %    be saved in =\count@=.
@@ -1302,12 +1413,42 @@
 % \changes{v2.0c}{1990/08/14}{\cs{relax} added to avoid problem
 %                           \cs{the}\cs{toks0}\cs{the}\cs{toks1}.}
 %    \begin{macrocode}
-   \the@toks \the \count@ \relax}
+   \the@toks \the \count@ \relax
 %    \end{macrocode}
+%
+%    And another socket for tagging that adds the necessary closing tag
+%    if enabled.
+% \changes{v2.6a}{2023/12/11}{Support for tagged PDF}
+%    \begin{macrocode}
+   \UseTaggingSocket{tbl/cell/end}%
+}
+%    \end{macrocode}
+%    Do the unskip only if we are in hmode:
+% \changes{v2.6b}{2024/04/08}{Do not \cs{unskip} if in math mode (gh/1323)}
+%    \begin{macrocode}
+\protected\def\textonly@unskip{\ifhmode\unskip\fi}
+%    \end{macrocode}
+% \end{macro}
 % \end{macro}
 % \end{macro}
 %
 %
+%  \begin{macro}{\insert@pcolumn}
+%    Handling pcolumn-cells needs slightly different handling when
+%    doing tagging.  Rather than changing the plugs in
+%    \cs{insert@column} back and forth, we simply use a different
+%    version of \cs{insert@column} that has its own sockets.
+% \changes{v2.6a}{2023/12/11}{Support for tagged PDF}
+%    \begin{macrocode}
+\def\insert@pcolumn{%
+   \UseTaggingSocket{tbl/pcell/begin}%
+   \the@toks \the \@tempcnta
+   \ignorespaces \@sharp \unskip
+   \the@toks \the \count@ \relax
+   \UseTaggingSocket{tbl/pcell/end}%
+}
+%    \end{macrocode}
+%  \end{macro}
 %
 %
 % \subsection{The separation of columns}
@@ -1321,11 +1462,24 @@
 %    =\@addamp=, the macro that inserts the =&=.
 %    \begin{macrocode}
 %    \newif \@iffirstamp
-%    \def\@addamp{\if@firstamp \@firstampfalse
-%                 \else \@addtopreamble &\fi}
+\def\@addamp {
+  \if@firstamp
+    \@firstampfalse
+  \else
+%    \end{macrocode}
+%    If we are after the first column we have to insert a \verb=&= and
+%    also update the cell data.
+% \changes{v2.6a}{2023/12/11}{Managing cell indexes}
+%    \begin{macrocode}
+    \edef\@preamble{\@preamble &
+      \noexpand\tbl_update_cell_data: }
+  \fi
+}
 %    \end{macrocode}
 % \end{macro}
 %
+%
+%
 % \begin{macro}{\@acol}
 % \begin{macro}{\@acolampacol}
 % \begin{macro}{\col@sep}
@@ -1393,7 +1547,7 @@
 %    command =\@xexpast=.  As we already know, this command saves
 %    its result in the macro =\@tempa=.
 %    \begin{macrocode}
-%   \@xexpast #1*0x\@@
+%   \@xexpast #1*0x\@@@@
 %    \end{macrocode}
 %    Afterwards we initialize all registers and macros, that we need
 %    for the build-up of the preamble.
@@ -1477,7 +1631,7 @@
 %    \texttt{r}, \texttt{p},\texttt{m} or \texttt{b}. We report an
 %    error and ignore the declaration given by ={..}=.
 %    \begin{macrocode}
-%   \@preamerr \thr@@ \or
+%   \@preamerr \thr@@@@ \or
 %    \end{macrocode}
 %    If =\@lastchclass= is $4$ the user preamble has been empty.
 %    To continue, we insert a =#= in the preamble.
@@ -1671,18 +1825,17 @@
     \setbox\ar@mcellbox\vbox
 %    \end{macrocode}
 %    The part of the templates which is the same in all three cases
-%    (\texttt{p}, \texttt{m} and \texttt{b})
-%    is built by the macros =\@startpbox= and
-%    =\@endpbox=. =\@startpbox= has an argument:
-%    the width of the column which is stored in the current
-%    \textsf{token} (i.e.\ =\@nextchar=).
-%    Between these two macros we find the well known
-%    =\insert@column=.
-%    The strut is places after the box
+%    (\texttt{p}, \texttt{m} and \texttt{b}) is built by the macros
+%    =\@startpbox= and =\@endpbox=. =\@startpbox= has an argument: the
+%    width of the column which is stored in the current \textsf{token}
+%    (i.e.\ =\@nextchar=).  Between these two macros we find the well
+%    known =\insert@column= or rather the variant for tagging:
+%    \cs{insert@pcolumn}.  The strut is placed after the box.
 % \changes{v2.4e}{2016/10/07}{Fixing SX68732}
 % \changes{v2.4f}{2017/11/04}{Managing m-cells without \cs{vcenter}}
+% \changes{v2.6a}{2023/12/11}{Support for tagged PDF}
 %    \begin{macrocode}
-    \@startpbox{\@nextchar}\insert@column \@endpbox
+    \@startpbox{\@nextchar}\insert@pcolumn \@endpbox
     \ar@align@mcell
     \do@row@strut \or
 %    \end{macrocode}
@@ -1690,9 +1843,10 @@
 %    same way though we do not need the =$= characters because we use
 %    =\vtop= or =\vbox=.
 % \changes{v2.4e}{2016/10/07}{Fixing SX68732}
+% \changes{v2.6a}{2023/12/11}{Support for tagged PDF}
 %    \begin{macrocode}
-   \vtop \@startpbox{\@nextchar}\insert@column \@endpbox\do@row@strut \or
-   \vbox \@startpbox{\@nextchar}\insert@column \@endpbox\do@row@strut
+   \vtop \@startpbox{\@nextchar}\insert@pcolumn \@endpbox\do@row@strut \or
+   \vbox \@startpbox{\@nextchar}\insert@pcolumn \@endpbox\do@row@strut
 %    \end{macrocode}
 %    Other values for =\@chnum= are impossible. Therefore we
 %    end the arguments to =\@addtopreamble= and =\ifcase=.
@@ -1783,8 +1937,8 @@
 %    So the declarations defined by the first  =>{...}=
 %    are ignored.
 %    \begin{macrocode}
-%\def\@classix{\ifnum \@lastchclass = \thr@@
-%       \@preamerr \thr@@ \fi
+%\def\@classix{\ifnum \@lastchclass = \thr@@@@
+%       \@preamerr \thr@@@@ \fi
 %    \end{macrocode}
 %    Furthermore, we call up =\@class10= because afterwards always a
 %    new column is started by \texttt{c}, \texttt{l}, \texttt{r},
@@ -1836,14 +1990,14 @@
 %    We only check if the last \textsf{token} was of class $3$ which is
 %    forbidden.
 %    \begin{macrocode}
-\def\@classvii{\ifnum \@lastchclass = \thr@@
+\def\@classvii{\ifnum \@lastchclass = \thr@@@@
 %    \end{macrocode}
 %    If this is true we output an error message and
 %    ignore the declarations stored
 %    by the last  =>{...}=, because these are overwritten
 %    by the argument of \texttt{@}.
 %    \begin{macrocode}
-   \@preamerr \thr@@ \fi}
+   \@preamerr \thr@@@@ \fi}
 %    \end{macrocode}
 % \end{macro}
 %
@@ -2032,7 +2186,7 @@
 %    second one describes the wanted preamble,
 %    e.g.\ it has the form =|c|c|c|=.
 %    \begin{macrocode}
-\def\@array[#1]#2{%
+\def\@array[#1]#2{
 %    \end{macrocode}
 %    First we define a \textsf{strut} whose size basically corresponds
 %     to a normal \textsf{strut} multiplied by the factor
@@ -2051,6 +2205,14 @@
              \@depth \arraystretch \dp \strutbox
              \@width \z@}%
 %    \end{macrocode}
+%    The total number of table columns of the current table is
+%    determined in \cs{tbl_count_table_cols:} but this is called in
+%    a group, so local settings do not survive. Thus, to save away the
+%    outer value of \cs{g_@@_table_cols_tl} we do it before the group.
+% \changes{v2.6a}{2023/12/11}{Support for tagged PDF}
+%    \begin{macrocode}
+  \tbl_save_outer_table_cols:
+%    \end{macrocode}
 %    Then we open a group, in which the user preamble is evaluated by
 %    the macro =\@mkpream=. As we know this must happen locally.
 %    This macro creates a preamble for a =\halign= and saves
@@ -2059,6 +2221,11 @@
   \begingroup
   \@mkpream{#2}%
 %    \end{macrocode}
+%    Figure out how many columns this table has:
+% \changes{v2.6a}{2023/12/11}{Managing cell indexes}
+%    \begin{macrocode}
+  \tbl_count_table_cols:
+%    \end{macrocode}
 %    We again redefine =\@preamble= so that a call up of =\@preamble=
 %    now starts the =\halign=. Thus also the arguments of \texttt{>},
 %    \texttt{<}, \texttt{@} and \texttt{!}, saved in the
@@ -2085,13 +2252,38 @@
 %    unsupported redefinition of a \TeX{} primitive for the moment (as people rely
 %    on that experimental code).
 %    \begin{macrocode}
-  \xdef\@preamble{\noexpand \ialign \@halignto
-                  \bgroup \@arstrut \@preamble
-                          \tabskip \z@ \cr}%
+  \xdef\@preamble{
+%    \end{macrocode}
+%    \cs{ialign} in the original definition is replaced by
+%    \cs{ar@ialign} defined below. This does what \cs{ialign} does but
+%    additionally handles the tagging structure for the whole table if necessary.
+% \changes{v2.6a}{2023/12/11}{Support for tagged PDF}
+%    \begin{macrocode}
+    \noexpand \ar@ialign
+    \@halignto
+       \bgroup \@arstrut
 %    \end{macrocode}
 %    What we have not explained yet is the macro =\@halignto=
 %    that was just used. Depending on its replacement text the
 %    =\halign= becomes a =\halign= \texttt{to} \meta{dimen}.
+%
+%    Next, a tagging support socket is inserted adding the start row tag.
+% \changes{v2.6a}{2023/12/11}{Support for tagged PDF}
+%    \begin{macrocode}
+      \UseTaggingSocket{tbl/row/begin}
+%    \end{macrocode}
+%    At the start of the preamble for the first column we call
+%    \cs{tbl_init_cell_data_for_row:} to initialize the cell index data. In
+%    later columns this data is updated via \cs{tbl_update_cell_data:}.
+% \changes{v2.6a}{2023/12/11}{Managing cell indexes}
+%    \begin{macrocode}
+      \tbl_init_cell_data_for_row:
+%    \end{macrocode}
+%    
+%    \begin{macrocode}
+      \@preamble
+      \tabskip \z@ \cr}
+%    \end{macrocode}
 %    Now we close the group again. Thus
 %    =\@startpbox= and =\@endpbox= as well as all
 %    \textsf{token} registers get their former meaning back.
@@ -2128,12 +2320,16 @@
 %    around every column in the \textsf{array}--environment
 %     the parameter =\mathsurround= should
 %    also be set to \textsf{0pt}. This prevents additional space between
-%    the rows. The
-%    \PlainTeX--macro =\m@th= does this.
+%    the rows.
 %    \begin{macrocode}
   \lineskip \z@
   \baselineskip \z@
-  \m@th
+%    \end{macrocode}
+%    Don't use \cs{m@th} here as that signals to the math taggingg
+%    code that this is fake math that should not be tagged.
+% \changes{v2.6a}{2023/12/11}{Support for tagged PDF}
+%    \begin{macrocode}
+  \mathsurround \z@
 %    \end{macrocode}
 %    Beside, we have to assign a special meaning (which we still have
 %    to specify) to the line separator =\\=. We also have to
@@ -2144,10 +2340,61 @@
 %    start the wanted =\halign=.
 %    \changes{1994/12/08}{v2.3b}{add \cs{tabularnewline}}
 %    \begin{macrocode}
-  \let\\\@arraycr \let\tabularnewline\\\let\par\@empty \@preamble}
+  \let\\\@arraycr \let\tabularnewline\\\let\par\@empty
+%    \end{macrocode}
+%    Another socket for tagging. TODO: what about \cs{arrayleft} above?
+%    \begin{macrocode}
+  \UseTaggingSocket{tbl/init}
+%    \end{macrocode}
+%
+%    \begin{macrocode}
+  \@preamble
+}
 %    \end{macrocode}
 % \end{macro}
 %
+%
+%
+% \begin{macro}{\ar@ialign}
+%    A new command that replaces \cs{ialign} used previously.  \cs{everycr} is
+%    also applied to the \cs{cr} ending the preamble so we have to
+%    program around that.
+% \changes{v2.6a}{2023/12/11}{Support for tagged PDF}
+%    \begin{macrocode}
+\def\ar@ialign{%
+%    \end{macrocode}
+%    Before starting a table we have to initialize the variables
+%    holding row and column information for cells. We also have
+%    locally store the information related to the current cell (if we
+%    are already inside a table) so that we can restore it once the
+%    inner table is finished.
+% \changes{v2.6a}{2023/12/11}{Managing cell indexes}
+%    \begin{macrocode}
+  \tbl_init_cell_data_for_table:
+%    \end{macrocode}
+%    
+%    \begin{macrocode}
+  \everycr{%
+    \noalign{%
+%    \end{macrocode}
+%    If this \cs{cr} was at the end of a real row (e.g., not at the
+%    end of the table preamble) we have add a row end tag. 
+%    \begin{macrocode}
+      \tbl_if_row_was_started:T  { \UseTaggingSocket{tbl/row/end} }
+%    \end{macrocode}
+%    The we prepare for the next row.
+%    \begin{macrocode}
+      \tbl_update_cell_data_for_next_row:
+    }%
+  }%
+  \tabskip\z@skip\halign}
+%    \end{macrocode}
+% \end{macro}
+%
+%
+%
+%
+%
 % \begin{macro}{\arraybackslash}
 % \changes{v2.4a}{2003/12/17}{(DPC) Macro added (from tabularx)}
 % Restore =\\= for use in array and tabular environment (after
@@ -2182,7 +2429,27 @@
 % \begin{macro}{\@arraycr}
 %    In the macro =\@array= the line separator =\\= is
 %    =\let= to the command =\@arraycr=.
-%    Its definition starts with a special brace which I have directly
+% \changes{v2.3c}{1995/04/23}{Avoid adding an ord atom in math}
+% \changes{v2.5e}{2021/04/20}{Use \cs{protected} for \cs{\bslash} variant (gh/548)}
+%    \begin{macrocode}
+\protected\def\@arraycr {
+%    \end{macrocode}
+%    Add code that figures out if the current table row is incomplete
+%    (not enough \verb=&=s). It can then do extra actions, such as
+%    inserting missing cell tags.
+% \changes{v2.6a}{2023/12/11}{Managing cell indexes}
+%    \begin{macrocode}
+  \tbl_count_missing_cells:n {@arraycr}
+%    \end{macrocode}
+%    TODO: maybe this is also the right place to add a socket that
+%    could be used to actually enter missing cells instead of just
+%    adding tagging structures for them later. This would be optional
+%    but in many cases it would be the right thing to do (for example
+%    if tables contain vertical lines or similar visual structures
+%    that require fully specified rows.
+%  
+%    
+%    We then start a special brace which I have directly
 %    copied from the original definition. It is
 %    necessary, because the =\futurlet= in =\@ifnextchar=
 %    might
@@ -2198,10 +2465,8 @@
 %    =\halign= while we are looking for a =*= or =[=.
 %    For further information see
 %    \cite[Appendix D]{bk:knuth}.
-% \changes{v2.3c}{1995/04/23}{Avoid adding an ord atom in math}
-% \changes{v2.5e}{2021/04/20}{Use \cs{protected} for \cs{\bslash} variant (gh/548)}
 %    \begin{macrocode}
-\protected\def\@arraycr{\relax\iffalse{\fi\ifnum 0=`}\fi
+  \iffalse{\fi\ifnum 0=`}\fi
 %    \end{macrocode}
 %    Then we test whether the user is using the star form and ignore
 %    a possible star (I also disagree with this procedure, because a
@@ -2210,6 +2475,11 @@
   \@ifstar \@xarraycr \@xarraycr}
 %    \end{macrocode}
 % \end{macro}
+
+
+
+
+
 %
 % \begin{macro}{\@xarraycr}
 %    In the command =\@xarraycr= we test if an optional argument
@@ -2301,6 +2571,7 @@
 %    the result column and the actual column entry.
 % \changes{v2.3j}{1998/01/29}{Command made \cs{long} to match
 %      kernel change for pr/2180}
+% \changes{v2.6a}{2023/12/11}{Support for tagged PDF}
 %    \begin{macrocode}
 \long\def\multicolumn#1#2#3{%
 %    \end{macrocode}
@@ -2310,6 +2581,16 @@
 %    \begin{macrocode}
    \multispan{#1}\begingroup
 %    \end{macrocode}
+%    For tagging support we have to solve two problems:
+%    \cs{multicolumn} must handle the row begin if it is used there,
+%    and it must save the numbers of cells it spans so that we can add
+%    a suitable ColSpan attribute. We do this in the next macro
+%    (which in turn calls the \texttt{tbl/row/begin} socket, if
+%    necessary).
+% \changes{v2.6a}{2023/12/11}{Managing cell indexes}
+%    \begin{macrocode}
+   \tbl_update_multicolumn_cell_data:n {#1}    
+%    \end{macrocode}
 %    Since a =\multicolumn= should only describe the format of a
 %    result column, we redefine =\@addamp= in such a way that one gets
 %    an error message if one uses more than one \texttt{c},
@@ -2336,6 +2617,12 @@
 %    \begin{macrocode}
    \endgroup
 %    \end{macrocode}
+%    Now we update the colspan attribute.  This needs setting after
+%    the group as it is hidden inside the plug in \cs{insert@column}.
+% \changes{v2.6a}{2023/12/11}{Support for tagged PDF}
+%    \begin{macrocode}
+   \UseTaggingSocket{tbl/colspan}{#1}%
+%    \end{macrocode}
 %    In the special situation of  =\multicolumn= =\@preamble=
 %    is not needed as preamble for a =\halign= but it is directly
 %    inserted into our table. Thus instead of =\sharp=
@@ -2458,6 +2745,12 @@
 %    \begin{macrocode}
   \leavevmode
 %    \end{macrocode}
+%    Now that we know we are in hmode we can add the start tag for the
+%    whole table.
+% \changes{v2.6a}{2023/12/11}{Support for tagged PDF}
+%    \begin{macrocode}
+  \UseTaggingSocket{tbl/hmode/begin}%
+%    \end{macrocode}
 %    It should be taken into consideration that the macro =\@array=
 %    must be called in math mode. Therefore we open a \textsf{box},
 %    insert a =$= and then assign the correct values to =\col@sep= and
@@ -2486,11 +2779,41 @@
 %    =\@array=. To save \textsf{token} space we then redefine
 %    =\@preamble=
 %    because its replacement text isn't longer needed.
+%
+%    To handle cell indexes, we do not use \cs{crcr} but a variant
+%    that also handles missing cells as necessary.
+% \changes{v2.6a}{2023/12/11}{Support for tagged PDF}
 %    \begin{macrocode}
-%\def\endarray{\crcr \egroup \egroup \gdef\@preamble{}}
+\def\endarray {
+  \tbl_crcr:n{endarray} \egroup
+  \UseTaggingSocket{tbl/finalize}
+%    \end{macrocode}
+%    
+%    If tables are nested into another then  it is necessary to
+%    restore information about the cell the inner table started
+%    in. Otherwise, the cell index data structures reflect the
+%    status in the outer table as they
+%    are globally manipulated. We restore in all cases even if we are
+%    not in a nesting situation as that makes the code simpler (and
+%    probably faster).
+%
+%    \cs{endtabular} and \cs{endtabular*} inherit from \cs{endarray}
+%    so we only need to change that. \texttt{tabularx} uses a similar method.
+% \changes{v2.6a}{2023/12/11}{Managing cell indexes}
+%    \begin{macrocode}
+  \tbl_restore_outer_cell_data:
+%    \end{macrocode}
+%    
+%    \begin{macrocode}
+  \egroup
+  \@arrayright \gdef\@preamble{}%
+}
 %    \end{macrocode}
 % \end{macro}
 %
+%
+%
+%
 % \begin{macro}{\endtabular}
 % \begin{macro}{\endtabular*}
 %    To end a \textsf{tabular} or \textsf{tabular$*$} environment we
@@ -2499,7 +2822,13 @@
 %    any =\mathsurround= so we cancel that with =\m@th=.
 % \changes{v2.5f}{2021/07/12}{Cancel any outside \cs{mathsurround} (gh/614)}
 %    \begin{macrocode}
-\def\endtabular{\endarray\m@th $\egroup}
+\def\endtabular{\endarray\m@th $\egroup
+%    \end{macrocode}
+%    
+% \changes{v2.6a}{2023/12/11}{Support for tagged PDF}
+%    \begin{macrocode}
+  \UseTaggingSocket{tbl/hmode/end}%
+}
 \expandafter\let\csname endtabular*\endcsname=\endtabular
 %    \end{macrocode}
 % \end{macro}
@@ -2518,7 +2847,7 @@
 \let\@arrayclassiv=\relax   \let\@arrayclassz=\relax
 \let\@tabclassiv=\relax     \let\@tabclassz=\relax
 \let\@arrayacol=\relax      \let\@tabacol=\relax
-\let\@tabularcr=\relax      \let\@@endpbox=\relax
+\let\@tabularcr=\relax      \let\@@@@endpbox=\relax
 \let\@argtabularcr=\relax   \let\@xtabularcr=\relax
 %    \end{macrocode}
 %
@@ -2576,6 +2905,7 @@
 % to define letters, to be used in the same way as the primitive
 % column specifiers, `c' `p' etc.
 %    \begin{macrocode}
+\ExplSyntaxOff  % this is really oldstyle using \@tfor :=
 \def\newcolumntype#1{%
 %    \end{macrocode}
 % "\NC@char" was added in V2.01 so that active characters, like "@" in
@@ -2615,6 +2945,7 @@
 % If an optional argument was not given, give a default argument of 0.
 %    \begin{macrocode}
   \@ifnextchar[{\newcol@{\NC@char}}{\newcol@{\NC@char}[0]}}
+\ExplSyntaxOn
 %    \end{macrocode}
 % \end{macro}
 % \begin{macro}{\newcol@}
@@ -2710,16 +3041,18 @@
 % produced and then "\typeout" the required string.
 %    \begin{macrocode}
 \def\NC@show#1{%
-  \typeout{Column #1\expandafter\expandafter\expandafter\NC@strip
-  \expandafter\meaning\csname NC@rewrite@#1\endcsname\@@}}
+  \typeout{Column~ #1\expandafter\expandafter\expandafter\NC@strip
+  \expandafter\meaning\csname NC@rewrite@#1\endcsname\@@@@}}
 %    \end{macrocode}
 % \end{macro}
 % \begin{macro}{\NC@strip}
 % Delimit the arguments to "\NC@strip" with `\texttt{:}', `\texttt{->}',
-% a space, and "\@@" to pull out the required parts of the output from
+% a space, and "\@@@@" to pull out the required parts of the output from
 % "\meaning".
 %    \begin{macrocode}
-\def\NC@strip#1:#2->#3 #4\@@{#2 -> #4}
+\ExplSyntaxOff
+\def\NC@strip#1:#2->#3 #4\@@@@{#2 -> #4}
+\ExplSyntaxOn
 %    \end{macrocode}
 % \end{macro}
 % \begin{macro}{\NC@list}
@@ -2807,6 +3140,7 @@
 % \changes{v2.4e}{2016/10/07}{Fixing SX68732}
 % \changes{v2.4f}{2017/11/04}{Managing m-cells without \cs{vcenter}}
 %    \begin{macrocode}
+\ExplSyntaxOff % really oldstyle using \@tfor :=
 \def\@mkpream#1{\gdef\@preamble{}\@lastchclass 4 \@firstamptrue
    \let\@sharp\relax
 %    \end{macrocode}
@@ -2869,11 +3203,12 @@
    \@acol \or
    \or
    \@acol \or
-   \@preamerr \thr@@ \or
+   \@preamerr \thr@@@@ \or
    \@preamerr \tw@ \@addtopreamble\@sharp \or
    \or
    \else  \@preamerr \@ne \fi
    \def\the@toks{\the\toks}}
+\ExplSyntaxOn
 %    \end{macrocode}
 % \end{macro}
 %
@@ -2908,7 +3243,7 @@
 % \texttt{array.sty} 2.0h.
 %    \begin{macrocode}
 \def\@classv{\save@decl
-   \expandafter\NC@ecs\@nextchar\extracolsep{}\extracolsep\@@@
+   \expandafter\NC@ecs\@nextchar\extracolsep{}\extracolsep\@@@@@@
    \@addtopreamble{\d@llarbegin\the@toks\the\count@\relax\d@llarend}%
    \prepnext@tok}
 %    \end{macrocode}
@@ -2920,7 +3255,7 @@
 % second "\extracolsep", there is no point in the user entering two of
 % these commands anyway, so this is not really a restriction.
 %    \begin{macrocode}
-\def\NC@ecs#1\extracolsep#2#3\extracolsep#4\@@@{\def\@tempa{#2}%
+\def\NC@ecs#1\extracolsep#2#3\extracolsep#4\@@@@@@{\def\@tempa{#2}%
   \ifx\@tempa\@empty\else\toks\count@={#1\tabskip#2\relax#3}\fi}
 %</ncols>
 %    \end{macrocode}
@@ -2936,28 +3271,27 @@
 %
 % \begin{macro}{\@tabarray}
 %    This macro tests for an optional bracket and then calls up
-%    "\@@array" or "\@@array[c]" (as default).
+%    "\@@@@array" or "\@@@@array[c]" (as default).
 %    \begin{macrocode}
 %<*package>
-\def\@tabarray{\@ifnextchar[{\@@array}{\@@array[c]}}
+\def\@tabarray{\@ifnextchar[{\@@@@array}{\@@@@array[c]}}
 %    \end{macrocode}
 % \end{macro}
-% \begin{macro}{\@@array}
+% \begin{macro}{\@@@@array}
 %    This macro tests could then test an optional delimiter before the
 %    left brace of the main preamble argument. Here in the main package
 %    it simply is let to be "\@array".
 %    \begin{macrocode}
-\let\@@array\@array
+\let\@@@@array\@array
 %    \end{macrocode}
 % \end{macro}
 %
-% \begin{macro}{\endarray}
+% \begin{macro}{\@arrrayleft}
 % \begin{macro}{\@arrayright}
 %    We have to declare the hook we put into "\@array" above.
-%    A similar hook `"\@arrayright"' will be inserted into the
+%    A similar hook \cs{@arrayright} will be inserted into the
 %    "\endarray" to gain control. Both defaults to empty.
 %    \begin{macrocode}
-\def\endarray{\crcr \egroup \egroup \@arrayright \gdef\@preamble{}}
 \let\@arrayleft\@empty
 \let\@arrayright\@empty
 %    \end{macrocode}
@@ -3182,6 +3516,14 @@
 %  \end{macro}
 %
 %
+%
+%
+%
+%    \begin{macrocode}
+\ExplSyntaxOff
+%    \end{macrocode}
+%
+%
 % \PrintIndex
 % \PrintChanges
 %
diff --git a/macros/latex/required/tools/array.pdf b/macros/latex/required/tools/array.pdf
index 085cb2321a..fd71de4045 100644
--- a/macros/latex/required/tools/array.pdf
+++ b/macros/latex/required/tools/array.pdf
diff --git a/macros/latex/required/tools/bm.dtx b/macros/latex/required/tools/bm.dtx
index a608c6aeb5..d7d6eb54ee 100644
--- a/macros/latex/required/tools/bm.dtx
+++ b/macros/latex/required/tools/bm.dtx
@@ -1,6 +1,6 @@
 % \iffalse meta-comment
 %
-% Copyright (C) 1993-2023
+% Copyright (C) 1993-2024
 %
 % The LaTeX Project and any individual authors listed elsewhere
 % in this file.
@@ -22,7 +22,7 @@
 % \fi
 %
 % \iffalse
-%% Copyright 1996 1997 1998 1999 2002 2003 2004 2016 2017 2019 2021 2022
+%% Copyright 1996 1997 1998 1999 2002 2003 2004 2016 2017 2019 2021 2022 2023
 %% David Carlisle Frank Mittelbach
 %%
 %% Development of this package was commissioned by Y&Y Inc.
@@ -36,7 +36,7 @@
 %<driver>\ProvidesFile{bm.drv}
 % \fi
 %         \ProvidesFile{bm.dtx}
-          [2023/07/08 v1.2f Bold Symbol Support (DPC/FMi)]
+          [2023/12/19 v1.2f Bold Symbol Support (DPC/FMi)]
 %
 % \iffalse
 %<*driver>
@@ -178,14 +178,14 @@
 % spacing). So the third example produces identical output to the first
 % (but \TeX\ takes more time producing it).
 %
-% In the fourth example the |\mathrm{\bm{g}}| is essentially
+% In the fourth example the |\mathrm{\bm{{g}}}| is essentially
 % equivalent to |\mathrm{\mbox{\boldmath$g$}}|. Currently math alphabet
 % settings are not passed down to `nested' math lists, and so in this
 % example, the |\mathrm| has no effect, and a bold math italic $\bm g$
 % is obtained.
 %
 % Similarly the last example is equivalent to
-% |$\mbox{\boldmath$\mathrm{g}$}}| and so in this case, one obtains a
+% |$\mbox{\boldmath$\mathrm{g}$}$| and so in this case, one obtains a
 % bold roman \textbf{g}.
 %
 % \subsection{Delimiters}
diff --git a/macros/latex/required/tools/bm.ins b/macros/latex/required/tools/bm.ins
index a7424a0e67..c0c8125d10 100644
--- a/macros/latex/required/tools/bm.ins
+++ b/macros/latex/required/tools/bm.ins
@@ -3,7 +3,7 @@
 %% driver files from the doc files in this package when run through
 %% LaTeX or TeX.
 %%
-%% Copyright (C) 1993-2023
+%% Copyright (C) 1993-2024
 %% The LaTeX Project and any individual authors listed elsewhere
 %% in this file.
 %%
@@ -45,7 +45,7 @@ The source is maintained by the LaTeX Project team and bug
 reports for it can be opened at https://latex-project.org/bugs/
 (but please observe conditions on bug reports sent to that address!)
 
-Copyright (C) 1993-2023
+Copyright (C) 1993-2024
 The LaTeX Project and any individual authors listed elsewhere
 in this file.
 
diff --git a/macros/latex/required/tools/bm.pdf b/macros/latex/required/tools/bm.pdf
index 47bef9fc86..96e7864915 100644
--- a/macros/latex/required/tools/bm.pdf
+++ b/macros/latex/required/tools/bm.pdf
diff --git a/macros/latex/required/tools/calc.dtx b/macros/latex/required/tools/calc.dtx
index 2c4cecbf03..154c6ba26a 100644
--- a/macros/latex/required/tools/calc.dtx
+++ b/macros/latex/required/tools/calc.dtx
@@ -1,6 +1,6 @@
 % \iffalse meta-comment
 %
-% Copyright (C) 1993-2023
+% Copyright (C) 1993-2024
 %
 % The LaTeX Project and any individual authors listed elsewhere
 % in this file.
diff --git a/macros/latex/required/tools/calc.pdf b/macros/latex/required/tools/calc.pdf
index 203c0032f6..bc73b49ab5 100644
--- a/macros/latex/required/tools/calc.pdf
+++ b/macros/latex/required/tools/calc.pdf
diff --git a/macros/latex/required/tools/changes.txt b/macros/latex/required/tools/changes.txt
index 0ced77d568..afd942a4e7 100644
--- a/macros/latex/required/tools/changes.txt
+++ b/macros/latex/required/tools/changes.txt
@@ -10,13 +10,80 @@ All changes above are only part of the development branch for the next release.
 ================================================================================
 
 #########################
+# 2023-11-01 Release
+#########################
+
+2024-05-23  Frank Mittelbach  <Frank.Mittelbach@latex-project.org>
+
+	* array.dtx:
+	* longtable.dtx:
+	* multicol.dtx:
+	* showkeys.dtx:
+	* varioref.dtx:
+	Do not error with "suspicous date" when rolling back to
+	early years of LaTeX2e (gh/1336)
+
+2024-05-09  Yukai Chou  <muzimuzhi@gmail.com>
+
+	* amsmath.dtx:
+	Fix typo in comment, \Umathcar -> \Umathchar (gh/1343)
+
+2024-04-10  Ulrike Fischer  <Ulrike.Fischer@latex-project.org>
+
+	* xr.dtx:
+	Merged in the code from xr-hyper. This extends xr to properly support
+	targets and links and also adds support for properties (gh/1180).
+
+2024-04-08  Frank Mittelbach  <Frank.Mittelbach@latex-project.org>
+
+	* array.dtx (section{The insertion of declarations):
+	Do not \unskip if in math mode, this way explicit spaces at the
+	end of the math cell remain as it is with array env in core LaTeX (gh/1323)
+
+2024-03-13  David Carlisle  <David.Carlisle@latex-project.org>
+
+	* l3sys-query.dtx
+	New package, providing a document interface to the l3sys-query Lua script.
+
+2024-01-22 Lars Madsen <daleif@math.au.dk>
+
+        * verbatim.dtx: added TAB marking support to \verbatiminput* (gh/1245)
+
+2023-12-16  David Carlisle  <David.Carlisle@latex-project.org>
+
+	* showkeys.dtx: avoid adding extra box to \@labels gh/1123
+
+2023-12-16  Frank Mittelbach  <Frank.Mittelbach@latex-project.org>
+
+	* longtable.dtx:
+	Support for tagged PDF
+	Manage and provide cell indexes
+
+2023-12-12  Frank Mittelbach  <Frank.Mittelbach@latex-project.org>
+
+	* array.dtx:
+	Support for tagged PDF
+	Manage and provide cell indexes
+
+2023-12-11  Frank Mittelbach  <Frank.Mittelbach@latex-project.org>
+
+	* tabularx.dtx:
+	Require newer LaTeX kernel (that supports tagging)
+	Suspend any tagging while doing trial typesetting
+
+2023-11-10  Frank Mittelbach  <Frank.Mittelbach@latex-project.org>
+
+	* multicol.dtx (subsection{Maintaining the mark registers}]):
+	Get rid of forced breaks for mark extraction (gh/1130)
+
+#########################
 # 2023-11-01c Release
 #########################
 
 2023-11-06  Frank Mittelbach  <Frank.Mittelbach@latex-project.org>
 
 	* verbatim.dtx (subsection{Preliminaries}):
-	Update code so that that \verb does not show visible spaces (gh/1160)
+	Update code so that \verb does not show visible spaces (gh/1160)
 
 #########################
 # 2023-11-01b Release
diff --git a/macros/latex/required/tools/dcolumn.dtx b/macros/latex/required/tools/dcolumn.dtx
index c8ddaf4ce6..feb3096cce 100644
--- a/macros/latex/required/tools/dcolumn.dtx
+++ b/macros/latex/required/tools/dcolumn.dtx
@@ -1,6 +1,6 @@
 % \iffalse meta-comment
 %
-% Copyright (C) 1993-2023
+% Copyright (C) 1993-2024
 %
 % The LaTeX Project and any individual authors listed elsewhere
 % in this file.
diff --git a/macros/latex/required/tools/dcolumn.pdf b/macros/latex/required/tools/dcolumn.pdf
index 95ad0bd449..bf7018beec 100644
--- a/macros/latex/required/tools/dcolumn.pdf
+++ b/macros/latex/required/tools/dcolumn.pdf
diff --git a/macros/latex/required/tools/delarray.dtx b/macros/latex/required/tools/delarray.dtx
index 86a1a6203f..61d40b5c74 100644
--- a/macros/latex/required/tools/delarray.dtx
+++ b/macros/latex/required/tools/delarray.dtx
@@ -1,6 +1,6 @@
 % \iffalse meta-comment
 %
-% Copyright (C) 1993-2023
+% Copyright (C) 1993-2024
 %
 % The LaTeX Project and any individual authors listed elsewhere
 % in this file.
diff --git a/macros/latex/required/tools/delarray.pdf b/macros/latex/required/tools/delarray.pdf
index dee83d0727..9a8d864bed 100644
--- a/macros/latex/required/tools/delarray.pdf
+++ b/macros/latex/required/tools/delarray.pdf
diff --git a/macros/latex/required/tools/enumerate.dtx b/macros/latex/required/tools/enumerate.dtx
index 2818a73a09..c3889a9157 100644
--- a/macros/latex/required/tools/enumerate.dtx
+++ b/macros/latex/required/tools/enumerate.dtx
@@ -1,6 +1,6 @@
 % \iffalse meta-comment
 %
-% Copyright (C) 1993-2023
+% Copyright (C) 1993-2024
 %
 % The LaTeX Project and any individual authors listed elsewhere
 % in this file.
diff --git a/macros/latex/required/tools/enumerate.pdf b/macros/latex/required/tools/enumerate.pdf
index 3cfae0299a..b83f030d7c 100644
--- a/macros/latex/required/tools/enumerate.pdf
+++ b/macros/latex/required/tools/enumerate.pdf
diff --git a/macros/latex/required/tools/fileerr.dtx b/macros/latex/required/tools/fileerr.dtx
index eef222bb6e..0e8eeb1ffb 100644
--- a/macros/latex/required/tools/fileerr.dtx
+++ b/macros/latex/required/tools/fileerr.dtx
@@ -1,6 +1,6 @@
 % \iffalse meta-comment
 %
-% Copyright (C) 1993-2023
+% Copyright (C) 1993-2024
 %
 % The LaTeX Project and any individual authors listed elsewhere
 % in this file.
diff --git a/macros/latex/required/tools/fileerr.pdf b/macros/latex/required/tools/fileerr.pdf
index c9ead205ae..664b3c49b7 100644
--- a/macros/latex/required/tools/fileerr.pdf
+++ b/macros/latex/required/tools/fileerr.pdf
diff --git a/macros/latex/required/tools/fontsmpl.dtx b/macros/latex/required/tools/fontsmpl.dtx
index 525065cde5..6e9835e20e 100644
--- a/macros/latex/required/tools/fontsmpl.dtx
+++ b/macros/latex/required/tools/fontsmpl.dtx
@@ -1,6 +1,6 @@
 % \iffalse meta-comment
 %
-% Copyright (C) 1993-2023
+% Copyright (C) 1993-2024
 %
 % The LaTeX Project and any individual authors listed elsewhere
 % in this file.
diff --git a/macros/latex/required/tools/fontsmpl.pdf b/macros/latex/required/tools/fontsmpl.pdf
index 400fc3cdb4..ba164a7eb0 100644
--- a/macros/latex/required/tools/fontsmpl.pdf
+++ b/macros/latex/required/tools/fontsmpl.pdf
diff --git a/macros/latex/required/tools/ftnright.dtx b/macros/latex/required/tools/ftnright.dtx
index 663fa304a9..a3826376db 100644
--- a/macros/latex/required/tools/ftnright.dtx
+++ b/macros/latex/required/tools/ftnright.dtx
@@ -1,6 +1,6 @@
 % \iffalse meta-comment
 %
-% Copyright (C) 1993-2023
+% Copyright (C) 1993-2024
 %
 % The LaTeX Project and any individual authors listed elsewhere
 % in this file.
diff --git a/macros/latex/required/tools/ftnright.pdf b/macros/latex/required/tools/ftnright.pdf
index b1ed43548d..12a83de3db 100644
--- a/macros/latex/required/tools/ftnright.pdf
+++ b/macros/latex/required/tools/ftnright.pdf
diff --git a/macros/latex/required/tools/hhline.dtx b/macros/latex/required/tools/hhline.dtx
index 49ac1ae208..b2d833d965 100644
--- a/macros/latex/required/tools/hhline.dtx
+++ b/macros/latex/required/tools/hhline.dtx
@@ -1,6 +1,6 @@
 % \iffalse meta-comment
 %
-% Copyright (C) 1993-2023
+% Copyright (C) 1993-2024
 %
 % The LaTeX Project and any individual authors listed elsewhere
 % in this file.
diff --git a/macros/latex/required/tools/hhline.pdf b/macros/latex/required/tools/hhline.pdf
index 9d389f0c7f..488b653aab 100644
--- a/macros/latex/required/tools/hhline.pdf
+++ b/macros/latex/required/tools/hhline.pdf
diff --git a/macros/latex/required/tools/indentfirst.dtx b/macros/latex/required/tools/indentfirst.dtx
index 2314db1c70..9bbe1871e1 100644
--- a/macros/latex/required/tools/indentfirst.dtx
+++ b/macros/latex/required/tools/indentfirst.dtx
@@ -1,6 +1,6 @@
 % \iffalse meta-comment
 %
-% Copyright (C) 1993-2023
+% Copyright (C) 1993-2024
 %
 % The LaTeX Project and any individual authors listed elsewhere
 % in this file.
diff --git a/macros/latex/required/tools/indentfirst.pdf b/macros/latex/required/tools/indentfirst.pdf
index 2aa538c345..b484dd82c9 100644
--- a/macros/latex/required/tools/indentfirst.pdf
+++ b/macros/latex/required/tools/indentfirst.pdf
diff --git a/macros/latex/required/tools/l3sys-query.dtx b/macros/latex/required/tools/l3sys-query.dtx
new file mode 100644
index 0000000000..3cba5da4a6
--- /dev/null
+++ b/macros/latex/required/tools/l3sys-query.dtx
@@ -0,0 +1,545 @@
+% \iffalse
+%% Source File: l3sys-query.dtx
+%% Copyright (C) 2024
+%%
+%% The LaTeX Project and any individual authors listed elsewhere
+%% in this file.
+%%
+%% This file may be distributed under the terms of the LPPL.
+%% See README for details.
+%
+%<*dtx>
+          \ProvidesFile{l3sys-query.dtx}
+%</dtx>
+%<package>\ProvidesPackage{l3sys-query}
+%<driver> \ProvidesFile{l3sys-query.drv}
+% \fi
+%         \ProvidesFile{l3sys-query.dtx}
+       [2024-03-28 v1.0a LaTeX2e interface for l3sys file queries]
+%
+% \iffalse
+%<*driver>
+\documentclass{l3doc}%{ltxdoc}
+\begin{document}
+\DocInput{l3sys-query.dtx}
+\end{document}
+%</driver>
+% \fi
+%
+% \GetFileInfo{l3sys-query.dtx}
+%
+% \title{\LaTeX\ document interface to the \pkg{l3sys-query} script:
+% System queries for LaTeX using Lua\thanks{This file
+%        has version number \fileversion, last
+%        revised \filedate.}}
+% \author{\LaTeX\ project}
+% \date{\filedate}
+%
+%
+% \maketitle
+%
+% \tableofcontents
+%
+% \section{Introduction}
+% 
+% \TeX{} engines provide only very limited access to information about the system
+% they are used on: using primitives, one can for example get the size of a single
+% file, but not a list of files in a given location. For most documents, this is
+% not an issue as they are self-contained. However, for cases where
+% \enquote{dynamic} construction of parts of a document is needed based on file
+% lists or other system-dependent data, methods to obtain this from (restricted)
+% shell escape are desirable.
+% 
+% Security considerations mean that directly querying the system shell is
+% problematic for general use. Instead, \emph{restricted} shell escape may be used
+% to get many details, provided a suitable tool is available to provide the
+% information in a platform-neutral and security-conscious way. The Java program
+% \texttt{texosquery}, written by Nicola Talbot, has been available for a number
+% of years to provide this facility. As well as file system insight,
+% \texttt{texosquery} also provides for example locale data and other system
+% information. However, the requirement for Java means that the script is not
+% automatically usable when a \TeX{} system is installed.
+% 
+% The \LaTeX{} team have therefore provided a Lua-based script,
+% \texttt{l3sys-query}, which conforms to the security requirements of \TeX{} Live
+% using Lua to obtain the system information. This means that it can be used
+% \enquote{out of the box} across platforms. The facilities provided by
+% \texttt{l3sys-query} are more limited than \texttt{texosquery}, partly as some
+% information is available in modern \TeX{} systems using primitives, and partly
+% as the aim of \texttt{l3sys-query} is to provide information where there are
+% defined use cases. Requests for additional data interfaces are welcome.
+%
+% This package provides a document level \textit{Key-Value} interface
+% to The \texttt{l3sys-query} functionality, although as a convenience
+% it also summarizes the documentation for the L3 programming
+% interface layer (prvided by the \pkg{l3sys} module of
+% \pkg{l3kernel}, and of the command line Lua script
+% \texttt{l3sys-query} which is distributed separately and provides
+% the underlying functionality.
+%
+% 
+% 
+% \section{The document level key-value  interface\label{sec:kv}}
+%
+% This provides an interface to \texttt{l3sys-query} based on
+% \pkg{l3keys} that allows the options to be specified and checked
+% individually. Internally the supplied key values are used to build
+% up the arguments to the commands described above in the L3
+% programming layer commands described in section~\ref{sec:expl3}
+%
+% Results containing path separators \emph{always}
+% use~|/|, irrespective of the platform in use.
+% 
+%
+% \begin{function}
+%   {\QueryWorkingDirectory}
+%   \begin{syntax}
+%     \cs{QueryWorkingDirectory} \Arg{result cmd}
+%   \end{syntax}
+%   Defines supplied command \meta{result cmd} to hold
+%   the absolute path to the current working directory of the
+%   \TeX\ system.
+%   This is the directory (folder) from which \TeX\ was started, so usually
+%   the location of the main document file.
+% \end{function}
+% 
+% \begin{function}
+%   {\QueryFiles, \QueryFilesTF}
+%   \begin{syntax}
+%     \cs{QueryFiles} \oarg{options} \Arg{spec} \Arg{function}
+%     \cs{QueryFilesTF} \oarg{options} \Arg{spec} \Arg{function} \Arg{pre code} \Arg{empty list code}
+%   \end{syntax}
+%   This generates a file list  based on the \meta{spec} and \meta{options}.
+%   The command then applies \meta{function}  to each item in the sequence of filenames.
+%   The \meta{function} should be a macro body which will be passed the file path as |#1|.
+% 
+%  The TF version executes the T (\meta{pre code}) argument before iterating over the list
+%  and the F (\meta{empty list code}) argument if the list is empty.
+% \end{function}
+% 
+%  Note that this interface in mapping directly over the sequence of
+%  filenames does not allow some uses which are provided by the
+%  programming interface described in the following section, which allows
+%  the sequence to be manipulated before being used.
+% 
+%  The defined keys map very closely to the options of the
+%  \texttt{l3sys-query} command which is described in
+%  section~\ref{sec:lua}.
+% 
+%  \begin{itemize}
+%  \item 
+%  The keys \texttt{recursive}, \texttt{ignore-case}, \texttt{reverse}, \texttt{pattern}
+%  take no values and map directly to the command line options of the same name.
+% 
+%  \item
+%  The key \texttt{sort} accepts the values \texttt{date} and \texttt{name}.
+% 
+%  \item
+%  The key \texttt{type} accepts \texttt{d} or \texttt{f}.
+% 
+%  \item
+%  The key \texttt{exclude} accepts a glob (or Lua pattern) matching
+%  files to be excluded.  The package arranges that the quoting of the
+%  argument is automatically added if unrestricted shell escape is
+%  enabled.
+% 
+% \end{itemize}
+% 
+%  Within the main \meta{spec} argument, and the value of the \texttt{exclude} key,
+%  the following characters may need special handling.
+%  |~| may be used (which \texttt{kpathsea} uses to denote the users home directory).
+%  |\%|, or at the top level |%|, may be used to produce a literal |%|
+%  which may be especially useful if the \texttt{pattern} key is used
+%  as \% is the escape character in Lua patterns.
+%  
+%  \subsection{Examples\label{sec:examples2e}}
+%
+%  \begin{itemize}
+%  \item 
+%  Include every |png| file in the current directory.
+% \begin{verbatim}
+% \QueryFiles{*.png}{\includegraphics{#1}\par}
+% \end{verbatim}
+%
+% \item
+%  Input every \TeX\ file with a filename matching \texttt{chapter[0-9].tex}.
+% \begin{verbatim}
+% \QueryFiles[pattern]{chapter%d.*%.tex}{\input{#1}}
+% \end{verbatim}
+%  \end{itemize}
+%
+% \section{The L3 programming layer interface\label{sec:expl3}}
+% 
+% \begin{function}
+%   {\sys_get_query:nN, \sys_get_query:nnN, \sys_get_query:nnnN}
+%   \begin{syntax}
+%     \cs{sys_get_query:nN} \Arg{cmd} \Arg{tl var}
+%     \cs{sys_get_query:nnN} \Arg{cmd} \Arg{spec} \Arg{tl var}
+%     \cs{sys_get_query:nnnN} \Arg{cmd} \Arg{options} \Arg{spec} \Arg{tl var}
+%   \end{syntax}
+%   Sets the \meta{tl var} to the information returned by the
+%   \texttt{l3sys-query} \meta{cmd}, potentially supplying the \meta{options}
+%   and \meta{spec} to the query call. The valid \meta{cmd} names are at present
+%   \begin{itemize}
+%     \item \texttt{pwd} Returns the absolute path to the current working directory
+%     \item \texttt{ls} Returns a directory listing, using the \meta{spec} to
+%       select files and applying the \meta{options} if given
+%   \end{itemize}
+%   The \meta{spec} should be a file glob and will automatically be passed to
+%   the script without shell expansion.
+% \end{function}
+% 
+% \begin{function}
+%   {\sys_split_query:nN, \sys_split_query:nnN, \sys_split_query:nnnN}
+%   \begin{syntax}
+%     \cs{sys_split_query:nN} \Arg{cmd} \Arg{seq}
+%     \cs{sys_split_query:nnN} \Arg{cmd} \Arg{spec} \Arg{seq}
+%     \cs{sys_split_query:nnnN} \Arg{cmd} \Arg{options} \Arg{spec} \Arg{seq}
+%   \end{syntax}
+%   Works as described for \cs{sys_get_query:nnnN}, but sets the \meta{seq}
+%   to contain one entry for each line returned by \texttt{l3sys-query}.
+% \end{function}
+% 
+% \section{The \texttt{l3sys-query} Lua script\label{sec:lua}}
+% \subsection{The command line interface}
+% 
+% The command line interface to 
+% \begin{center}
+%   \ttfamily
+%   l3sys-query \meta{cmd} [\meta{option(s)}] [\meta{args}]
+% \end{center}
+% where \texttt{\meta{cmd}} can be one of the following:
+% \begin{itemize}[noitemsep]\ttfamily
+%   \item ls
+%   \item ls \meta{args}
+%   \item pwd
+% \end{itemize}
+% The \meta{cmd} are described below. The result of the \meta{cmd} will be printed
+% to the terminal in an interactive run; in normal usage, this will be piped to
+% the calling \TeX{} process. Results containing path separators \emph{always}
+% use~|/|, irrespective of the platform in use.
+% 
+% As well as these targets, the script recognizes the options
+% \begin{itemize}
+%   \item |--exclude| Specification for directory entries to exclude
+%   \item |--ignore-case| Ignores case when sorting directory listings
+%   \item |--pattern| (|-p|) Treat the \meta{args} as Lua patterns rather
+%     than converting from wildcards
+%   \item |--recursive| (|-r|) Enables recursive searching during directory
+%     listings
+%   \item |--reverse| Causes sorting to go from highest to lowest rather
+%     than lowest to highest
+%   \item |--sort| Sets the method used to sort entries returned by |ls|
+%   \item |--type| Selects the type of entry returned by |ls|
+% \end{itemize}
+% The action of these options on the appropriate \meta{cmd(s)} is detailed below.
+% 
+% \subsubsection{\texttt{ls [\meta{args}]}}
+% 
+% Lists the contents of one or more directories, in a manner somewhat reminiscent
+% of the Unix command |ls| or the Windows command |dir|. The exact nature of the
+% output will depend on the \meta{args}, if given, along with the prevailing
+% options. Note that the options names are inspired by ideas from the Unix
+% commands |ls| and |find| as well as the Windows command |dir|: they therefore do
+% not map directly to those of any one of the command line tools that they
+% somewhat mirror.
+% 
+% When no \meta{args} are given, all entries in the current directory will be
+% listed, one per line in the output. This will include both files and
+% subdirectories. Each entry will include a path relative to the current
+% directory: for files \emph{in} the current directory, this will be |./|. The
+% order of results will be determined by the underlying operating system process:
+% unless requested \emph{via} an option, no sorting takes place.
+% 
+% As standard, the \meta{args} are treated as a file/path name potentially
+% including |?| and |*| as wildcards, for example |*.png| or |file?.txt|.
+% \begin{verbatim}
+%   l3sys-query ls '*.png'
+% \end{verbatim}
+% Some care is needed in preventing expansion of such wildcards by the shell or
+% \texttt{texlua} process: these are detailed in Section~\ref{sec:wildcard}. In
+% this section, |'| is used to indicate a character being used to suppress
+% expansion: this is for example normal on macOS and Linux.
+% 
+% Removal of entries from the listing can be achieved using the |--exclude|
+% option, which should be given with a \meta{xarg}, for example
+% \begin{verbatim}
+%   l3sys-query ls --exclude '*.bak' 'graphics/*'
+% \end{verbatim}
+% Directory entries starting |.| are traditionally hidden on Linux and macOS
+% systems: these \enquote{dot} entries are excluded from the output of
+% \texttt{l3sys-query}. The entries |.| and |..| for the current and parent
+% directory are also excluded from the results returned by \texttt{l3sys-query} as
+% they can always be assumed.
+% 
+% For more complex matching, the \meta{args} can be treated as a Lua pattern using
+% the |--pattern| (|-p|) option; this also applies to the \meta{xarg} argument to
+% the |--exclude| option. For example, the equivalent to wildcard |*.png| could be
+% obtained using
+% \begin{verbatim}
+%   l3sys-query ls --pattern '^.*%.png$'
+% \end{verbatim}
+% 
+% The results returned by |ls| can be sorted using the |--sort| option. This can
+% be set to |none| (use the order from the file system: the default), |name| (sort
+% by file name) or |date| (sort by date last modified). The sorting order can be
+% reversed using |--reverse|. Sorting normally takes account of case: this can be
+% suppressed with the |--ignore-case| option.
+% 
+% The listing can be filtered based on the type of entry using the |--type|
+% option. This takes a string argument, one of |d| (directory) or |f| (file).
+% 
+% As standard, only the path specified as part of the \meta{args} is queried.
+% However, if the |--recursive| (|-r|) option is set, the query is applied within
+% all subdirectories. Subdirectories starting with~|.| (macOS and Linux hidden)
+% are excluded from recursion.
+% 
+% For security reasons, only paths within the current working directory can be
+% queried, thus for example |graphics/*.png| will list all |png| files in the
+% |graphics| subdirectory, but |../graphics/*.png| will yield no output.
+% 
+% \subsubsection{\texttt{pwd}}
+% 
+% Returns the current working directory from which \texttt{l3sys-query} is run.
+% From within a \TeX{} run, this will (usually) be the directory containing the
+% main file, assuming a command such as
+% \begin{verbatim}
+%   pdflatex main.tex
+% \end{verbatim}
+% The \texttt{pwd} command is unaffected by any options.
+% 
+% \subsection{Spaces in arguments}
+% 
+% Since \texttt{l3sys-query} is intended primarily for use with restricted shell
+% escape calls from \TeX{} processes, handling of spaces is unusual. It is not
+% possible to quote spaces in such a call, so for example whilst
+% \begin{verbatim}
+%   l3sys-query ls "foo *"
+% \end{verbatim}
+% does work from the command prompt to find all files with names starting
+% \verb*|foo |, it would not work \emph{via} restricted shell escape. To
+% circumvent this, \texttt{l3sys-query} will collect all command line arguments
+% after any \meta{options}, and combine these as a space-separated \meta{args},
+% for example allowing
+% \begin{verbatim}
+%   l3sys-query ls foo '*'
+% \end{verbatim}
+% to achieve the same result as the first example. The result is that the
+% \meta{args} will only every be interpreted by \texttt{l3sys-query} as a single
+% argument. It also means that spaces cannot be used at the start or end of the
+% argument, nor can multiple spaces appear between non-space arguments.
+% 
+% \subsection{Wildcard expansion handling\label{sec:wildcard}}
+% 
+% The handling of wildcards needs some further comment for those using
+% \texttt{l3sys-query} from the command line: the \pkg{expl3} interface described
+% in Section~\ref{sec:expl3} handles this aspect automatically for the user.
+% 
+% On macOS and Linux, the shell normally expands globs, which include the
+% wildcards |*| and |?|, before passing arguments to the appropriate command.
+% This can be suppressed by surrounding the argument with |'| characters, hence
+% the formulation
+% \begin{verbatim}
+%   l3sys-query ls '*.png'
+% \end{verbatim}
+% earlier.
+% 
+% On Windows, the shell does no expansion, and thus arguments are passed as-is to
+% the relevant command. As such, |'| has no special meaning here. However, to
+% allow quoting of wildcards from the shell in a platform-neutral manner,
+% \texttt{l3sys-query} will strip exactly one set of |'| characters around each
+% argument before further processing.
+% 
+% It is not possible to use |"| quotes at all in the argument passed to
+% \texttt{l3sys-query} from \TeX{}, as the \TeX{} system removes all |"| in
+% |\input| while handling space quoting.
+% 
+% Restricted shell escape prevents shell expansion of wildcards entirely. On
+% non-Windows systems, it does this by ensuring that each argument is |'| quoted
+% to ensure further expansion. Thus a \TeX{} call such as
+% \begin{verbatim}
+%   \input|"l3sys-query ls '*.png'"
+% \end{verbatim}
+% will work if |--shell-escape| is used as the argument is passed directly to the
+% shell, but in restricted shell escape will give an error such as:
+% \begin{verbatim}
+% ! I can't find file `"|l3sys-query ls '*.png'"'.
+% \end{verbatim}
+% The \LaTeX{} interfaces described above adjust the quoting used depending on the
+% |shell-escape| status.
+% 
+% 
+% \MaybeStop{}
+%
+% \section{The \LaTeXe\ package implementation}
+%
+%    \begin{macrocode}
+%<*package>
+%    \end{macrocode}
+%
+%    \begin{macrocode}
+\ExplSyntaxOn
+%<@@=queryfiles>
+%    \end{macrocode}
+%
+% The package should eventually work in restricted shell escape but will do
+% nothing useful if the process was started with |--no-shell-escape|.
+%    \begin{macrocode}
+\sys_if_shell:F{
+  \PackageWarningNoLine{l3sys-query}
+  {Shell ~Escape ~is ~disabled.\MessageBreak All ~queries ~will ~return ~empty ~results}
+  }
+%    \end{macrocode}
+%
+% \subsection{\cs{QueryWorkingDirectory}}
+% |\QueryWorkingDirectory| is a direct call to the |pwd| command provided by \texttt{l3sys-query}.
+%    \begin{macrocode}
+\NewDocumentCommand\QueryWorkingDirectory {m} {
+  \sys_get_query:nN {pwd} #1
+}
+%    \end{macrocode}
+%
+% \subsection{\cs{QueryFiles} and \cs{QueryFilesTF}}
+%
+% The declarations of these commands are done in two steps to allow catcode chanes
+% before the arguments are read. This allows the use of |%| and |^^| in patterns
+% at least if the command is not nested in another command argument. (|\%| may be used
+% to generate |%| in all cases).
+%
+% Variables for saving the current definition of |\%| and |~|.
+%    \begin{macrocode}
+\tl_new:N\l_query_percent_tl
+\tl_new:N\l_query_tilde_tl
+%    \end{macrocode}
+%
+% Allow |%| and |^^| at the top level.
+%    \begin{macrocode}
+\NewDocumentCommand\QueryFiles {} {
+  \group_begin:
+    \char_set_catcode_other:N \%
+    \char_set_catcode_other:N \^
+    \QueryFiles_inner
+  }
+%    \end{macrocode}
+%
+%    \begin{macrocode}
+\char_set_catcode_active:N \~
+%    \end{macrocode}
+%
+%    \begin{macrocode}
+\NewDocumentCommand\QueryFiles_inner {O{}m}{
+  \group_end:
+  \tl_set:Nn\l_tmpa_tl{}
+  \cs_set_eq:NN  \l_query_percent_tl \%
+  \cs_set_eq:NN  \% \c_percent_str
+  \cs_set_eq:NN  \l_query_tilde_tl ~
+  \cs_set_eq:NN  ~ \c_tilde_str
+  \keys_set:nn{QueryFiles}{#1}
+  \exp_args:NnV\sys_split_query:nnnN {ls} \l_tmpa_tl {#2} \l_tmpa_seq
+  \cs_set_eq:NN  \% \l_query_percent_tl
+  \cs_set_eq:NN  ~ \l_query_tilde_tl
+  \seq_map_inline:Nn\l_tmpa_seq
+}
+%    \end{macrocode}
+%
+% This duplicates rather than shares code so as to read the function
+% and TF arguments with normal catcode regime.
+% (This could probably be optimised.)
+%    \begin{macrocode}
+\NewDocumentCommand\QueryFilesTF {} {
+  \group_begin:
+    \char_set_catcode_other:N \%
+    \QueryFilesTF_inner
+ }
+%    \end{macrocode}
+%
+%    \begin{macrocode}
+\NewDocumentCommand\QueryFilesTF_inner {O{}m}{
+  \group_end:
+  \tl_set:Nn\l_tmpa_tl{}
+  \cs_set_eq:NN  \l_query_percent_tl \%
+  \cs_set_eq:NN  \% \c_percent_str
+  \cs_set_eq:NN  \l_query_tilde_tl ~
+  \cs_set_eq:NN  ~ \c_tilde_str
+  \keys_set:nn{QueryFiles}{#1}
+  \exp_args:NnV\sys_split_query:nnnN {ls} \l_tmpa_tl {#2} \l_tmpa_seq
+  \cs_set_eq:NN  \% \l_query_percent_tl
+  \cs_set_eq:NN  ~ \l_query_tilde_tl
+  \seq_if_empty:NTF \l_tmpa_seq \use_iii:nnn \__queryfiles_aux:nnn
+}
+%    \end{macrocode}
+%
+%    \begin{macrocode}
+\char_set_catcode_space:N \~
+%    \end{macrocode}
+%
+%    \begin{macrocode}
+\cs_new:Npn  \__queryfiles_aux:nnn #1#2#3 {
+    #2
+    \seq_map_inline:Nn\l_tmpa_seq {#1}
+ }
+%    \end{macrocode}
+%
+% Defining the keys. Most take no value and simply add a \texttt{l3sys-query} \texttt{-{}-}
+% option to the command linebeing constructed.
+%    \begin{macrocode}
+\keys_define:nn {QueryFiles} {
+%    \end{macrocode}
+%
+%    \begin{macrocode}
+recursive .code:n  =\tl_put_right:Nn \l_tmpa_tl {--recursive ~ } ,
+recursive .value_forbidden:n = true ,
+%    \end{macrocode}
+%
+%    \begin{macrocode}
+ignore-case .code:n  =\tl_put_right:Nn \l_tmpa_tl {--ignore-case ~ } ,
+ignore-case .value_forbidden:n = true ,
+%    \end{macrocode}
+%
+%    \begin{macrocode}
+reverse .code:n  =\tl_put_right:Nn \l_tmpa_tl {--reverse ~ } ,
+reverse .value_forbidden:n = true ,
+%    \end{macrocode}
+%
+%    \begin{macrocode}
+exclude .code:n  =\tl_put_right:Ne \l_tmpa_tl {
+  --exclude ~
+  \sys_if_shell_restricted:F'
+  \exp_not:n{#1}
+  \sys_if_shell_restricted:F'
+  ~ } ,
+exclude .value_required:n = true ,
+%    \end{macrocode}
+%
+% The |type| key checks the supplied value is valid |d| for directories
+% or |f| for files The default behaviour lists both.
+%    \begin{macrocode}
+type .choices:nn = {d,f}
+                   {\tl_put_right:Nn \l_tmpa_tl {--type ~ #1 ~ }} ,
+%    \end{macrocode}
+%
+% The |sort| key checks the supplied value is valid |date| or |name|.
+%    \begin{macrocode}
+sort .choices:nn = {date,name}
+{\tl_put_right:Nn \l_tmpa_tl {--sort ~ #1 ~ }} ,
+%    \end{macrocode}
+%
+%    \begin{macrocode}
+pattern .code:n  =\tl_put_right:Nn \l_tmpa_tl {--pattern ~ } ,
+pattern .value_forbidden:n = true ,
+%    \end{macrocode}
+%
+%    \begin{macrocode}
+}
+%    \end{macrocode}
+%
+%    \begin{macrocode}
+\ExplSyntaxOff
+%    \end{macrocode}
+%
+%    \begin{macrocode}
+%</package>
+%    \end{macrocode}
+%
+% \Finale
+%
diff --git a/macros/latex/required/tools/l3sys-query.ins b/macros/latex/required/tools/l3sys-query.ins
new file mode 100644
index 0000000000..163eec0058
--- /dev/null
+++ b/macros/latex/required/tools/l3sys-query.ins
@@ -0,0 +1,76 @@
+%%
+%% This file will generate fast loadable files and documentation
+%% driver files from the doc files in this package when run through
+%% LaTeX or TeX.
+%%
+%% Copyright (C) 1993-2024
+%% The LaTeX Project and any individual authors listed elsewhere
+%% in this file.
+%%
+%% This file is part of the Standard LaTeX `Tools Bundle'.
+%% -------------------------------------------------------
+%%
+%% It may be distributed and/or modified under the
+%% conditions of the LaTeX Project Public License, either version 1.3c
+%% of this license or (at your option) any later version.
+%% The latest version of this license is in
+%%    https://www.latex-project.org/lppl.txt
+%% and version 1.3c or later is part of all distributions of LaTeX
+%% version 2005/12/01 or later.
+%%
+%% As this file contains legal notices, it is NOT PERMITTED to modify
+%% this file in any way that the legal information placed into
+%% generated files is changed (i.e., the files generated when the
+%% original file is executed). This restriction does not apply if
+%% (parts of) the content is reused in a different WORK producing its
+%% own generated files.
+%%
+%% The list of all files belonging to the `Tools Bundle' is
+%% given in the file `manifest.txt'.
+%%
+%%
+%% --------------- start of docstrip commands ------------------
+%%
+\input docstrip
+
+\keepsilent
+
+\usedir{tex/latex/tools}
+
+\preamble
+
+This is a generated file.
+
+The source is maintained by the LaTeX Project team and bug
+reports for it can be opened at https://latex-project.org/bugs/
+(but please observe conditions on bug reports sent to that address!)
+
+Copyright (C) 1993-2024
+The LaTeX Project and any individual authors listed elsewhere
+in this file.
+
+This file was generated from file(s) of the Standard LaTeX `Tools Bundle'.
+--------------------------------------------------------------------------
+
+It may be distributed and/or modified under the
+conditions of the LaTeX Project Public License, either version 1.3c
+of this license or (at your option) any later version.
+The latest version of this license is in
+   https://www.latex-project.org/lppl.txt
+and version 1.3c or later is part of all distributions of LaTeX
+version 2005/12/01 or later.
+
+This file may only be distributed together with a copy of the LaTeX
+`Tools Bundle'. You may however distribute the LaTeX `Tools Bundle'
+without such generated files.
+
+The list of all files belonging to the LaTeX `Tools Bundle' is
+given in the file `manifest.txt'.
+
+\endpreamble
+
+\keepsilent
+
+\generate{\file{l3sys-query.sty}{\from{l3sys-query.dtx}{package}}}
+
+\endbatchfile
diff --git a/macros/latex/required/tools/l3sys-query.pdf b/macros/latex/required/tools/l3sys-query.pdf
new file mode 100644
index 0000000000..5ec3ca9511
--- /dev/null
+++ b/macros/latex/required/tools/l3sys-query.pdf
diff --git a/macros/latex/required/tools/layout.dtx b/macros/latex/required/tools/layout.dtx
index 2798bd4f60..a2fc87a6a5 100644
--- a/macros/latex/required/tools/layout.dtx
+++ b/macros/latex/required/tools/layout.dtx
@@ -1,6 +1,6 @@
 % \iffalse meta-comment
 %
-% Copyright (C) 1993-2023
+% Copyright (C) 1993-2024
 %
 % The LaTeX Project and any individual authors listed elsewhere
 % in this file.
diff --git a/macros/latex/required/tools/layout.pdf b/macros/latex/required/tools/layout.pdf
index 30ba99447f..634b7320a4 100644
--- a/macros/latex/required/tools/layout.pdf
+++ b/macros/latex/required/tools/layout.pdf
diff --git a/macros/latex/required/tools/longtable-2020-01-07.sty b/macros/latex/required/tools/longtable-2020-01-07.sty
index f79c691e10..fc7c3f4290 100644
--- a/macros/latex/required/tools/longtable-2020-01-07.sty
+++ b/macros/latex/required/tools/longtable-2020-01-07.sty
@@ -1,4 +1,8 @@
 %%
+%% This is an old release of `longtable.sty' used during rollback operations.
+%% Do not use this file directly.
+%% ==============================
+%%
 %% This is file `longtable.sty',
 %% generated with the docstrip utility.
 %%
diff --git a/macros/latex/required/tools/longtable.dtx b/macros/latex/required/tools/longtable.dtx
index 2a61ab0c87..cc3a939e7a 100644
--- a/macros/latex/required/tools/longtable.dtx
+++ b/macros/latex/required/tools/longtable.dtx
@@ -1,6 +1,6 @@
 % \iffalse meta-comment
 %
-% Copyright (C) 1993-2023
+% Copyright (C) 1993-2024
 %
 % The LaTeX Project and any individual authors listed elsewhere
 % in this file.
@@ -27,8 +27,9 @@
           \ProvidesFile{longtable.dtx}
 %</dtx>
 %<package>\NeedsTeXFormat{LaTeX2e}[1995/06/01]
-%<package>\providecommand\DeclareRelease[3]{}
-%<package>\providecommand\DeclareCurrentRelease[2]{}
+%<package>
+% Try the 2020 version for any rollback before that date:          
+%<package>\DeclareRelease{}{1994-06-01}{longtable-2020-01-07.sty}
 %<package>
 %<package>\DeclareRelease{v4.13}{2020-01-02}{longtable-2020-01-07.sty}
 %<package>\DeclareCurrentRelease{}{2020-02-07}
@@ -37,7 +38,7 @@
 %<driver> \ProvidesFile{longtable.drv}
 % \fi
 %         \ProvidesFile{longtable.dtx}
-          [2023-11-01 v4.19 Multi-page Table package (DPC)]
+          [2024-04-26 v4.20 Multi-page Table package (DPC)]
 %
 % \iffalse
 %<*driver>
@@ -1048,6 +1049,14 @@
   \if@twocolumn
     \LT@err{longtable not in 1-column mode}\@ehc
   \fi
+%    \end{macrocode}
+%    
+% \changes{v4.19}{2023/12/16}{Support for tagged PDF}
+%    \begin{macrocode}
+  \UseTaggingSocket{tbl/vmode/begin}%
+%    \end{macrocode}
+%    
+%    \begin{macrocode}
   \begingroup
 %    \end{macrocode}
 % Check for an optional argument.
@@ -1056,7 +1065,14 @@
 %    \end{macrocode}
 % \end{macro}
 %
+%
+%
 % \begin{macro}{\LT@array}
+%    \begin{macrocode}
+%<@@=tbl>
+\ExplSyntaxOn
+%    \end{macrocode}
+%
 % Start setting the alignment.
 % Based on "\@array" from the \LaTeX\ kernel
 % and the \package{array} package.
@@ -1066,7 +1082,43 @@
 % so that "\caption" works correctly.
 %    \begin{macrocode}
 \def\LT@array[#1]#2{%
-  \refstepcounter{table}\stepcounter{LT@tables}%
+%    \end{macrocode}
+%
+%    With respect to tagging we have a complicated situation with
+%    longtable. When at the begin the \cs{endhead},
+%    \cs{endfirsthead}, \cs{endfoot} and \cs{endlastfoot} are used to
+%    setup head and foot they create each a structure subtree with one or
+%    more rows. From these structures we want to keep at most two (head
+%    and foot) and move the foot to the end of the table. When the head
+%    and foot boxes are (re)inserted on following pages we want to mark
+%    them up as artifact with the exception of the head at the begin and
+%    the foot box at the end.
+%
+%    TODO: When a line is killed the structure subtree is there already
+%    too and must be removed. If hard to do, then maybe at first warn if the
+%    construction is used.
+%  
+%    \cs{LT@array} is executed in a group, so we can disable para-tagging here.
+% \changes{v4.19}{2023/12/16}{Support for tagged PDF}
+%    \begin{macrocode}
+  \UseTaggingSocket{tbl/init}
+  \@kernel@refstepcounter{table}\stepcounter{LT@tables}
+%    \end{macrocode}
+% The target is created rather late and a \cs{label} can come earlier, 
+% so we have to define \cs{@currentHref} explicitly. We can't currently
+% assume that \cs{theHtable} is defined always.
+%    \begin{macrocode}
+  \tl_gset:Ne \@currentHref {table.\cs_if_exist_use:N\theHtable}
+%    \end{macrocode}
+%    
+% \changes{v4.19}{2023/12/16}{Managing cell indexes}
+%    \begin{macrocode}
+  \tbl_gzero_row_count:
+%    \end{macrocode}
+%    
+% \changes{v4.19}{2023/12/16}{Support for tagged PDF}
+%    \begin{macrocode}
+  \UseTaggingSocket{tbl/longtable/init}
 %    \end{macrocode}
 % Set up the glue around the table if an optional argument given.
 %    \begin{macrocode}
@@ -1101,17 +1153,18 @@
 % here so that you can load the \package{array} package before or after
 % \package{longtable}.
 %    \begin{macrocode}
-  \let\LT@@tabarray\@tabarray
-  \let\LT@@hl\hline
+  \let\LT@@@@tabarray\@tabarray
+  \let\LT@@@@hl\hline
   \def\@tabarray{%
-    \let\hline\LT@@hl
+    \let\hline\LT@@@@hl
 %    \end{macrocode}
 %\begin{verbatim}
 %    \let\multicolumn\LT@mcol
 %\end{verbatim}
 %    \begin{macrocode}
-    \LT@@tabarray}%
-  \let\\\LT@tabularcr\let\tabularnewline\\%
+    \LT@@@@tabarray}%
+  \let\\\LT@tabularcr
+  \let\tabularnewline\\%
   \def\newpage{\noalign{\break}}%
 %    \end{macrocode}
 % \changes{v4.05}{1996/11/12}
@@ -1128,8 +1181,8 @@
 %    \end{macrocode}
 %
 % \changes{v4.08}{1998/01/20}
-%      {Move \cs{@endpbox} definition earlier and define \cs{@@endpbox}
-%      and \cs{@@startpbox} for non-array case. tools/2736}
+%      {Move \cs{@endpbox} definition earlier and define \cs{@@@@endpbox}
+%      and \cs{@@@@startpbox} for non-array case. tools/2736}
 %    \begin{macrocode}
   \let\@endpbox\LT@endpbox
 %    \end{macrocode}
@@ -1142,8 +1195,8 @@
     \let\@acol\@tabacol
     \let\@classz\@tabclassz \let\@classiv\@tabclassiv
     \def\@startpbox{\vtop\LT@startpbox}%
-    \let\@@startpbox\@startpbox
-    \let\@@endpbox\@endpbox
+    \let\@@@@startpbox\@startpbox
+    \let\@@@@endpbox\@endpbox
     \let\LT@LL@FM@cr\@tabularcr
   \else
 %    \end{macrocode}
@@ -1172,6 +1225,11 @@
    \begingroup
     \@mkpream{#2}%
 %    \end{macrocode}
+%    
+% \changes{v4.19}{2023/12/16}{Managing cell indexes}
+%    \begin{macrocode}
+    \tbl_count_table_cols:
+%    \end{macrocode}
 % We need to rename "\@preamble" here as F.M.'s scheme uses
 % "\global", and we may need to nest "\@mkpream", eg for
 % "\multicolumn"
@@ -1180,6 +1238,11 @@
 %    \begin{macrocode}
     \xdef\LT@bchunk{%
 %    \end{macrocode}
+%    We aren't inside any row when a chunk starts.
+% \changes{v4.19}{2023/12/16}{Managing cell indexes}
+%    \begin{macrocode}
+      \tbl_inbetween_rows:
+%    \end{macrocode}
 % \changes{v4.00}{1996/04/08}
 %      {(DK) Increment Chunk counter}
 %    \begin{macrocode}
@@ -1205,7 +1268,21 @@
 %    \begin{macrocode}
        \tabskip\LTleft \noexpand\halign to\hsize\bgroup
 %       \tabskip\LTleft\halign to\hsize\bgroup
-      \tabskip\z@ \@arstrut \@preamble \tabskip\LTright \cr}%
+       \tabskip\z@ \@arstrut
+%    \end{macrocode}
+%    Insert the tagging socket to start the row and initialize the cell
+%    data for the row.  
+% \changes{v4.19}{2023/12/16}{Support for tagged PDF}
+%    \begin{macrocode}
+       \UseTaggingSocket{tbl/row/begin}%
+%    \end{macrocode}
+%    
+% \changes{v4.19}{2023/12/16}{Managing cell indexes}
+%    \begin{macrocode}
+       \tbl_init_cell_data_for_row:
+%    \end{macrocode}
+%    \begin{macrocode}
+       \@preamble \tabskip\LTright \cr}%
   \endgroup
 %    \end{macrocode}
 % Find out how many columns we have (store in "\LT@cols").
@@ -1220,11 +1297,57 @@
 % A few more internal commands for \env{longtable}.
 %    \begin{macrocode}
   \m@th\let\par\@empty
-  \everycr{}\lineskip\z@\baselineskip\z@
+%    \end{macrocode}
+% Tagging socket and conditional
+%    \begin{macrocode}
+  \everycr{%
+    \noalign{%
+%    \end{macrocode}
+%    In \pkg{longtable} we have a bunch of extra \cs{cr}s that are
+%    executed whenever a chunk ends. In that case they should not
+%    increment the main row counter, sigh.
+%
+%    TODO: At the moment this tracing still exposes the internal row counter!
+%    \begin{macrocode}
+      \@@_trace:n {--longtable-->~chunk~row:~ \the\LT@rows \space
+                   row:~ \the\g_@@_row_int   \space
+                   column:~ \the\g_@@_col_int
+      }
+%    \end{macrocode}
+%    
+% \changes{v4.19}{2023/12/16}{Support for tagged PDF}
+%    \begin{macrocode}
+      \tbl_if_row_was_started:T
+          {
+            \UseTaggingSocket{tbl/row/end}
+%    \end{macrocode}
+%    The next setting prevents any of the additional \cs{cr}s at the end of the
+%    chunk to add another /TR. Then once we really start a new chunk
+%    it gets incremented so\ldots
+% \changes{v4.19}{2023/12/16}{Managing cell indexes}
+%    \begin{macrocode}
+            \tbl_inbetween_rows:
+          }
+%    \end{macrocode}
+%    And for the same reason such \cs{cr}s should not increment the
+%    main row counter (but it has to be incremented after the preamble
+%    of a chunk), so here we test against \cs{LT@rows} which is
+%    \cs{LTchunksize} at the end of a chunk.
+% \changes{v4.19}{2023/12/16}{Managing cell indexes}
+%    \begin{macrocode}
+      \int_compare:nNnT \LT@rows < \LTchunksize
+         { \tbl_gincr_row_count: }   % next is row about to start
+    }%
+  }%
+%    \end{macrocode}
+%    \begin{macrocode}
+  \lineskip\z@\baselineskip\z@
 %    \end{macrocode}
 % Start the first chunk.
 %    \begin{macrocode}
   \LT@bchunk}
+\ExplSyntaxOff
+%<@@=>
 %    \end{macrocode}
 % \end{macro}
 %
@@ -1251,6 +1374,11 @@
 % force the page-breaker to wake up. The second "\endgraf" is there so
 % that "\pagetotal" is updated and so takes "\LTpre" into account.
 %    \begin{macrocode}
+%<@@=tbl>
+\ExplSyntaxOn
+%    \end{macrocode}
+%
+%    \begin{macrocode}
 \def\LT@start{%
   \let\LT@start\endgraf
   \endgraf\penalty\z@\vskip\LTpre\endgraf
@@ -1334,7 +1462,7 @@
 % \changes{v3.14}{1995/05/02}
 %      {Set \cs{@colroom}, for tools/1584}
 %    \begin{macrocode}
-      \global\@colroom\@colht
+ \global\@colroom\@colht
 %    \end{macrocode}
 % If the foot is non empty, reduce the "\vsize" and "\@colroom"
 % accordingly.
@@ -1342,24 +1470,46 @@
 %      {Rearrange vertical space tests for tools/3512 (floats on same page)}
 %    \begin{macrocode}
   \ifvoid\LT@foot\else
-%    \advance\vsize-\ht\LT@foot
     \global\advance\vsize-\ht\LT@foot
     \global\advance\@colroom-\ht\LT@foot
     \dimen@\pagegoal\advance\dimen@-\ht\LT@foot\pagegoal\dimen@
     \maxdepth\z@
   \fi
 %    \end{macrocode}
+%    
+%    \begin{macrocode}
+  \MakeLinkTarget{table}
+%    \end{macrocode}
 % Put the table head on the page, and then switch to the new output
 % routine.
 % \changes{v4.11}{2004/02/01}
 %      {\cs{nobreak}, for tools/3484}
 %    \begin{macrocode}
   \ifvoid\LT@firsthead\copy\LT@head\else\box\LT@firsthead\fi\nobreak
+%    \end{macrocode}
+%    
+% \changes{v4.19}{2023/12/16}{Support for tagged PDF}
+%    \begin{macrocode}
+  \UseTaggingSocket{tbl/longtable/head}
+%    \end{macrocode}
+%    
+%    \begin{macrocode}
   \output{\LT@output}}
+\ExplSyntaxOff
+%<@@=>
 %    \end{macrocode}
 % \end{macro}
 %
+%
+%
+%
 % \begin{macro}{\endlongtable}
+%
+%    \begin{macrocode}
+%<@@=tbl>
+\ExplSyntaxOn
+%    \end{macrocode}
+%
 % Called by "\end{longtable}".
 %    \begin{macrocode}
 \def\endlongtable{%
@@ -1370,11 +1520,23 @@
 % been shortened, or the table numbering has gone awry). In that case
 % we at least start collecting valid new information with the last
 % chunk of this table, by removing the width constraint.
+% \changes{v4.19}{2023/12/16}{Support for tagged PDF}
+%    \begin{macrocode}
+  \tbl_crcr:n {endlongtable}
+%    \end{macrocode}
+%    
 % \changes{v4.01}{1996/04/11}
 %      {(DPC) use \cs{noalign} to sneak in \cs{LT@entry@chop}}
 %    \begin{macrocode}
-  \crcr
   \noalign{%
+%    \end{macrocode}
+%    
+% \changes{v4.19}{2023/12/16}{Support for tagged PDF}
+%    \begin{macrocode}
+    \UseTaggingSocket{tbl/longtable/finalize}
+%    \end{macrocode}
+%    
+%    \begin{macrocode}
     \let\LT@entry\LT@entry@chop
     \xdef\LT@save@row{\LT@save@row}}%
   \LT@echunk
@@ -1414,10 +1576,10 @@
 % \changes{v4.04}{1996/05/24}
 %      {Use \cs{LT@final@warn}}
 %    \begin{macrocode}
-  \ifx\LT@save@row\LT@@save@row
+  \ifx\LT@save@row\LT@@@@save@row
   \else
-    \LT@warn{Column \@width s have changed\MessageBreak
-             in table \thetable}%
+    \LT@warn{Column~ widths~ have~ changed\MessageBreak
+             in~ table~ \thetable}%
     \LT@final@warn
   \fi
 %    \end{macrocode}
@@ -1449,7 +1611,15 @@
 %    \end{macrocode}
 % Footnotes. As done in  the \package{multicol} package.
 %    \begin{macrocode}
-  \ifvoid\footins\else\insert\footins{}\fi}
+  \ifvoid\footins\else\insert\footins{}\fi
+%    \end{macrocode}
+%    
+% \changes{v4.19}{2023/12/16}{Support for tagged PDF}
+%    \begin{macrocode}
+  \UseTaggingSocket{tbl/vmode/end}%
+}
+\ExplSyntaxOff
+%<@@=>
 %    \end{macrocode}
 % \end{macro}
 %
@@ -1518,6 +1688,10 @@
 \protected\def\LT@tabularcr{%
   \relax\iffalse{\fi\ifnum0=`}\fi
   \@ifstar
+%    \end{macrocode}
+%    TODO: as we replace crcr later in one case, we probably have to
+%    implement some further logic there!
+%    \begin{macrocode}
     {\def\crcr{\LT@crcr\noalign{\nobreak}}\let\cr\crcr
      \LT@t@bularcr}%
     {\LT@t@bularcr}}
@@ -1544,8 +1718,13 @@
 %    \end{macrocode}
 % \end{macro}
 %
+%
+%
+%
 % \begin{macro}{\LT@t@bularcr}
 %    \begin{macrocode}
+%<@@=tbl>
+\ExplSyntaxOn
 \def\LT@t@bularcr{%
 %    \end{macrocode}
 % Increment the counter, and do  \env{tabular}'s "\\" or finish the
@@ -1555,6 +1734,13 @@
 %    \begin{macrocode}
   \global\advance\LT@rows\@ne
   \ifnum\LT@rows=\LTchunksize
+%    \end{macrocode}
+%    At the end of the chunk \verb=\\= is doing something special and
+%    so we lose \verb=\tbl_count_missing_cells:n=. Below is about the
+%    right place to add it do this code branch.
+% \changes{v4.19}{2023/12/16}{Managing cell indexes}
+%    \begin{macrocode}
+    \tbl_count_missing_cells:n {echunk}
     \gdef\LT@setprevdepth{%
       \prevdepth\z@
       \global\let\LT@setprevdepth\relax}%
@@ -1563,6 +1749,8 @@
     \ifnum0=`{}\fi
     \expandafter\LT@LL@FM@cr
   \fi}
+\ExplSyntaxOff
+%<@@=>
 %    \end{macrocode}
 % \end{macro}
 %
@@ -1943,7 +2131,9 @@
 % This code is based on "\cline". Two copies of the line are produced,
 % as described above.
 %    \begin{macrocode}
-\def\LT@@hline{%
+%<@@=tbl>
+\ExplSyntaxOn
+\def\LT@@@@hline{%
   \ifx\@let@token\hline
     \global\let\@gtempa\@gobble
     \gdef\LT@sep{\penalty-\@medpenalty\vskip\doublerulesep}%
@@ -1954,11 +2144,25 @@
   \ifnum0=`{\fi}%
   \multispan\LT@cols
      \unskip\leaders\hrule\@height\arrayrulewidth\hfill\cr
-  \noalign{\LT@sep}%
+%    \end{macrocode}
+%    Don't update the row counter, or rather undo the update done in \cs{everycr}:
+% \changes{v4.19}{2023/12/16}{Managing cell indexes}
+%    \begin{macrocode}
+  \noalign{
+    \tbl_gdecr_row_count:
+    \LT@sep}
   \multispan\LT@cols
      \unskip\leaders\hrule\@height\arrayrulewidth\hfill\cr
-  \noalign{\penalty\@M}%
+%    \end{macrocode}
+%    Same here.
+% \changes{v4.19}{2023/12/16}{Managing cell indexes}
+%    \begin{macrocode}
+  \noalign{
+    \tbl_gdecr_row_count:
+    \penalty\@M}
   \@gtempa}
+\ExplSyntaxOff
+%<@@=>
 %    \end{macrocode}
 % \end{macro}
 %
@@ -2049,13 +2253,15 @@
 % \begin{macro}{\LT@output}
 %     Actually this is not so bad, with FM leading the way.
 %    \begin{macrocode}
+%<@@=tbl>
+\ExplSyntaxOn
 \def\LT@output{%
   \ifnum\outputpenalty <-\@Mi
     \ifnum\outputpenalty > -\LT@end@pen
 %    \end{macrocode}
 %     If this was a float or a marginpar we complain.
 %    \begin{macrocode}
-      \LT@err{floats and marginpars not allowed in a longtable}\@ehc
+      \LT@err{floats~ and~ marginpars~ not~ allowed~ in~ a~ longtable}\@ehc
     \else
 %    \end{macrocode}
 % We have reached the end of the table, on the scroll at least,
@@ -2103,6 +2309,13 @@
 %    \begin{macrocode}
         \unvbox\z@\box\ifvoid\LT@lastfoot\LT@foot\else\LT@lastfoot\fi
 %    \end{macrocode}
+%    Handle foot box when tagging:
+%
+% \changes{v4.19}{2023/12/16}{Support for tagged PDF}
+%    \begin{macrocode}
+        \UseTaggingSocket{tbl/longtable/foot}
+%    \end{macrocode}
+%
 % End of "\ifnum\outputpenalty > -\LT@end@pen".
 %    \begin{macrocode}
     \fi
@@ -2114,6 +2327,15 @@
 % If we have not reached the end of the table,
 %    \begin{macrocode}
     \setbox\@cclv\vbox{\unvbox\@cclv\copy\LT@foot\vss}%
+%    \end{macrocode}
+%
+%    Handle foot box when tagging:
+% \changes{v4.19}{2023/12/16}{Support for tagged PDF}
+%    \begin{macrocode}
+    \UseTaggingSocket{tbl/longtable/foot}
+%    \end{macrocode}
+%
+%    \begin{macrocode}
     \@makecol
     \@outputpage
 %    \end{macrocode}
@@ -2133,8 +2355,15 @@
 %    \begin{macrocode}
   \fi}
 %    \end{macrocode}
+%
+%    \begin{macrocode}
+\ExplSyntaxOff
+%<@@=>
+%    \end{macrocode}
 % \end{macro}
 %
+%
+%
 % \subsection{Commands for the table head and foot}
 %
 % \begin{macro}{\LT@end@hd@ft}
@@ -2142,20 +2371,86 @@
 % box specified by "#1". Issue an error if the table has already
 % started. Then start a new chunk.
 %    \begin{macrocode}
+%<@@=tbl>
+\ExplSyntaxOn
 \def\LT@end@hd@ft#1{%
+%    \end{macrocode}
+%    
+%    This command is used to store the head and foot boxes.
+%    We need to retrieve and store the row so that we can clean
+%    up the structure in the finalize code.
+%
+%    To handle missing columns in the header we need this:
+% \changes{v4.19}{2023/12/16}{Managing cell indexes}
+%    \begin{macrocode}
+  \tbl_if_row_was_started:TF
+     {
+%    \end{macrocode}
+%    TODO: This is exposing internal counters, so it should be encapsulated
+%    in some interface command (but I'm not sure what that should be
+%    called, so not done yet. 
+% \changes{v4.19}{2023/12/16}{Managing cell indexes}
+%    \begin{macrocode}
+       \tbl_count_missing_cells:n {head/foot}
+       \int_step_inline:nn
+         { \LT@rows + 1 }
+         {
+           \seq_gput_left:ce
+             {g_@@_\cs_to_str:N #1 _rows_seq }
+             { \int_eval:n {\g_@@_row_int + 1 - ##1 } }
+         }
+%    \end{macrocode}
+%    We also have to set the chunk rows to its max value before
+%    calling \cs{LTechunk} so that we don't get extra increments of
+%    the main row counter due to \cs{everycr}.
+%    \begin{macrocode}
+       \int_gset:Nn \LT@rows { \LTchunksize }
+     }
+%    \end{macrocode}
+
+%    If  we are still in column zero then we had an empty \cs{endhead}
+%    and so making any assignment, etc., would start a row --- something we don't want.
+%    To get out of this trap we  run \cs{crcr} (which would normally
+%    come inside \cs{LT@echunk}. That will then trigger \cs{everycr}
+%    and update row counter unnecessarily, but now we have a defined state, so
+%    we can use \cs{noalign} to undo that. 
+%    We also change \cs{LT@rows} so that further \cs{cr}s do not do
+%    any harm (as explained above.
+%
+%    The \cs{crcr} inside \cs{LT@echunk} will be bypassed in that case
+%    as we have just executed a \cs{crcr} and are still in scanning modus for
+%    \cs{omit} or \cs{noalign}.     
+%    \begin{macrocode}
+     {
+       \crcr
+       \noalign{
+%    \end{macrocode}
+%    
+% \changes{v4.19}{2023/12/16}{Managing cell indexes}
+%    \begin{macrocode}
+         \tbl_gdecr_row_count:         % undo the increment
+         \int_gset:Nn \LT@rows { \LTchunksize }
+       }
+     }
   \LT@echunk
 %    \end{macrocode}
 % Changed from "\relax" to "\endgraf" at V3.04, see "\LT@start".
 %    \begin{macrocode}
   \ifx\LT@start\endgraf
     \LT@err
-     {Longtable head or foot not at start of table}%
-     {Increase LTchunksize}%
+     {Longtable~ head~ or~ foot~ not~ at~ start~ of~ table}%
+     {Increase~ LTchunksize}%
   \fi
   \setbox#1\box\z@
+  \@@_trace:n {-->>~ Saving~\noexpand#1}  
   \LT@get@widths
   \LT@bchunk}
 %    \end{macrocode}
+%
+%    \begin{macrocode}
+\ExplSyntaxOff
+%<@@=>
+%    \end{macrocode}
 % \end{macro}
 %
 % \begin{macro}{\endfirsthead}
@@ -2255,6 +2550,24 @@
 %    \end{macrocode}
 % \end{macro}
 %
+%
+%
+%
+%
+%    Some variables need for the tagging support.
+%    \begin{macrocode}
+%<@@=tbl>
+\ExplSyntaxOn
+   \seq_new:N \g_@@_LT@firsthead_rows_seq
+   \seq_new:N \g_@@_LT@head_rows_seq
+   \seq_new:N \g_@@_LT@lastfoot_rows_seq
+   \seq_new:N \g_@@_LT@foot_rows_seq
+\ExplSyntaxOff
+%<@@=>
+%    \end{macrocode}
+%
+%
+%
 %    \begin{macrocode}
 %</package>
 %    \end{macrocode}
diff --git a/macros/latex/required/tools/longtable.ins b/macros/latex/required/tools/longtable.ins
index 5c3ad27063..60b7461571 100644
--- a/macros/latex/required/tools/longtable.ins
+++ b/macros/latex/required/tools/longtable.ins
@@ -3,7 +3,7 @@
 %% driver files from the doc files in this package when run through
 %% LaTeX or TeX.
 %%
-%% Copyright (C) 1993-2023
+%% Copyright (C) 1993-2024
 %% The LaTeX Project and any individual authors listed elsewhere
 %% in this file.
 %%
@@ -45,7 +45,7 @@ The source is maintained by the LaTeX Project team and bug
 reports for it can be opened at https://latex-project.org/bugs/
 (but please observe conditions on bug reports sent to that address!)
 
-Copyright (C) 1993-2023
+Copyright (C) 1993-2024
 The LaTeX Project and any individual authors listed elsewhere
 in this file.
 
diff --git a/macros/latex/required/tools/longtable.pdf b/macros/latex/required/tools/longtable.pdf
index 406dee682f..4a3b54a16f 100644
--- a/macros/latex/required/tools/longtable.pdf
+++ b/macros/latex/required/tools/longtable.pdf
diff --git a/macros/latex/required/tools/multicol-2017-04-11.sty b/macros/latex/required/tools/multicol-2017-04-11.sty
index 9e346656bb..bdebc93db9 100644
--- a/macros/latex/required/tools/multicol-2017-04-11.sty
+++ b/macros/latex/required/tools/multicol-2017-04-11.sty
@@ -1,5 +1,7 @@
 %%
-%% This is an old release of `multicol.sty',
+%% This is an old release of `multicol.sty' used during rollback operations.
+%% Do not use this file directly.
+%% ==============================
 %%
 %% The source is maintained by the LaTeX Project team and bug
 %% reports for it can be opened at http://latex-project.org/bugs.html
diff --git a/macros/latex/required/tools/multicol-2019-10-01.sty b/macros/latex/required/tools/multicol-2019-10-01.sty
index 221f62f68e..fc8bda5479 100644
--- a/macros/latex/required/tools/multicol-2019-10-01.sty
+++ b/macros/latex/required/tools/multicol-2019-10-01.sty
@@ -1,6 +1,7 @@
-%% This is a rollback file for multicol to the last version within release 2019-10-01
-%% =======================
 %%
+%% This is an old release of `multicol.sty' used during rollback operations.
+%% Do not use this file directly.
+%% ==============================
 %%
 %% This is file `multicol.sty',
 %% generated with the docstrip utility.
@@ -101,14 +102,6 @@
 %%
 %%     Frank.Mittelbach@latex-project.org
 %%
-\NeedsTeXFormat{LaTeX2e}[2018-04-01]
-
-\providecommand\DeclareRelease[3]{}
-\providecommand\DeclareCurrentRelease[2]{}
-
-\DeclareRelease{}{2017-04-11}{multicol-2017-04-11.sty}
-\DeclareCurrentRelease{}{2018-04-01}
-
 \ProvidesPackage{multicol}
           [2019/12/09 v1.8y  multicolumn formatting (FMi)]
 %%
diff --git a/macros/latex/required/tools/multicol.dtx b/macros/latex/required/tools/multicol.dtx
index 2676d03aa1..4d86448002 100644
--- a/macros/latex/required/tools/multicol.dtx
+++ b/macros/latex/required/tools/multicol.dtx
@@ -86,11 +86,10 @@
 %<*dtx>
           \ProvidesFile{multicol.dtx}
 %</dtx>
-%<package>\NeedsTeXFormat{LaTeX2e}[2018-04-01]
-%<package>
-%<package>\providecommand\DeclareRelease[3]{}
-%<package>\providecommand\DeclareCurrentRelease[2]{}
 %<package>
+% For any rollback before 2017 load the 2017 version and hope for the best:          
+%<package>\DeclareRelease{}{1994-06-01}{multicol-2017-04-11.sty}
+%
 %<package>\DeclareRelease{}{2017-04-11}{multicol-2017-04-11.sty}
 %<package>\DeclareRelease{v1.8}{2019-10-01}{multicol-2019-10-01.sty}
 %<package>\DeclareCurrentRelease{}{2021-11-15}
@@ -99,10 +98,10 @@
 %<driver> \ProvidesFile{multicol.drv}
 % \fi
 %         \ProvidesFile{multicol.dtx}
-          [2023/03/30 v1.9f  multicolumn formatting (FMi)]
+          [2024/05/23 v1.9h  multicolumn formatting (FMi)]
+%
 %
 %
-%%
 %
 % \changes{v1.9c}{2021/11/30}{Added rollback to v1.8}
 % \changes{v1.5n}{1997/06/05}{Applied improvement of documentation,
@@ -919,9 +918,22 @@
 %    And we don't show macro names in the margin.
 %    \begin{macrocode}
 \setcounter{IndexColumns}{4}
-\let\DescribeMacro\SpecialUsageIndex
-\let\DescribeEnv\SpecialEnvIndex
-\renewcommand\PrintMacroName[1]{}
+%    \end{macrocode}
+%
+%    The following redefinitions have to be moved until after the
+%    preamble because version 3 of \pkg{doc} resets them after the
+%    premable (this is tmp, because \pkg{hypdoc} is not yet
+%    integrated, but as we all know, tmp solutions have a tendency to
+%    survive for a long time\ldots).
+%    \begin{macrocode}
+\AddToHook{begindocument}{%
+  \let\DescribeMacro\SpecialUsageIndex
+  \let\DescribeEnv\SpecialEnvIndex
+  \renewcommand\PrintMacroName[1]{}%
+}
+%    \end{macrocode}
+%
+%    \begin{macrocode}
 \CodelineIndex
 %\DisableCrossrefs           % Partial index
 \RecordChanges               % Change log
@@ -1082,7 +1094,7 @@
 %    better test for this situation. Otherwise, we will get a \TeX{}
 %    stack overflow as this would generate a self-referencing definition.
 % \changes{v1.6e}{2004/02/14}{Avoid self-referencing definition of
-%    \cs{@footnotetext} (pr/3618)}.
+%    \cs{@footnotetext} (pr/3618)}
 %    \begin{macrocode}
      \ifx\@footnotetext\mult@footnotetext
      \else
@@ -2376,7 +2388,7 @@
 %    If |\raggedcolumns| is in force we add a |vfill| at the bottom by
 %    unboxing the split box.
 %    But we need to unbox anyway to ensure that at the end of the box
-%    we do not have unwanted space. This can sneak in in certain
+%    we do not have unwanted space. This can sneak in, in certain
 %    situations, for example, if two lists follow each other and we
 %    break between them. While such space is usually zero it still has
 %    an effect because it hides depth of the last line in the column
@@ -2925,7 +2937,11 @@
 %    We start by setting the kept marks by updating them with any
 %    marks from this box. This has to be done \emph{before} we add a
 %    penalty of $-10000$ to the top of the box, otherwise only an
-%    empty box will be considered.
+%    empty box will be considered. But even that is not enough: the box
+%    may contain \cs{columnbreak}s in which case doing some artifical
+%    splitting to get the marks out still fails to see all marks
+%    unless we take some special precaution in \cs{get@keptmarks}
+%    (which is now done).
 % \changes{v1.5h}{1994/08/26}{Get kept marks first}
 %    \begin{macrocode}
    \get@keptmarks\mult@box
@@ -3751,8 +3767,15 @@
 %    everything is split off. As a result |\splitfirstmark| and
 %    |\splitbotmark| will contain the first and last mark in the box
 %    respectively.
+%
+%    Unfortunately, a simple \cs{vsplit} is not enough if the material
+%    contains forced breaks in that case we first have to get rid of
+%    those which is why we do this work in a separate macro that can
+%    call itself recursively.
+% \changes{v1.9g}{2023/11/10}{Get rid of forced breaks for mark
+%      extraction (gh/1130)}
 %    \begin{macrocode}
-   \setbox#1\vsplit#1to\maxdimen
+   \mc@get@all@box@marks #1%
 %    \end{macrocode}
 %    Therefore we can now set the kept marks which is a global
 %    operation and afterwards close the group. This will restore the
@@ -3773,6 +3796,29 @@
 %  \end{macro}
 %
 %
+%  \begin{macro}{\mc@get@all@box@marks}
+%    This macro splits a box to \cs{maxdimen} in order to get at the
+%    marks inside. If it turns out that we have a remainder after the
+%    split (e.g., if there was a \cs{columnbreak} in the material) we
+%    stitch the two parts together again (which omits the forced
+%    break) and recurse. Eventually, everything is split off and the
+%    split marks will then have the appropriate values.
+% \changes{v1.9g}{2023/11/10}{Get rid of forced breaks for mark
+%      extraction (gh/1130)}
+%    \begin{macrocode}
+\def\mc@get@all@box@marks #1{%
+  \setbox\@tempboxa\vsplit#1to\maxdimen
+  \ifvoid#1\else
+    \setbox#1\vbox{\unvbox\@tempboxa \unvbox#1}%
+    \mc@get@all@box@marks #1%
+  \fi
+}
+%    \end{macrocode}
+%  \end{macro}
+%
+%
+%
+%
 %  \begin{macro}{\set@keptmarks}
 %    The macro |\set@keptmarks| is responsible for setting
 %    |\kept@firstmark| and |\kept@botmark|, by checking the current
diff --git a/macros/latex/required/tools/multicol.ins b/macros/latex/required/tools/multicol.ins
index fa561e0bb1..7a7ef27d24 100644
--- a/macros/latex/required/tools/multicol.ins
+++ b/macros/latex/required/tools/multicol.ins
@@ -3,7 +3,7 @@
 %% driver files from the doc files in this package when run through
 %% LaTeX or TeX.
 %%
-%% Copyright (C) 1993-2023
+%% Copyright (C) 1993-2024
 %% The LaTeX Project and any individual authors listed elsewhere
 %% in this file.
 %%
@@ -45,7 +45,7 @@ The source is maintained by the LaTeX Project team and bug
 reports for it can be opened at https://latex-project.org/bugs/
 (but please observe conditions on bug reports sent to that address!)
 
-Copyright (C) 1993-2023
+Copyright (C) 1993-2024
 The LaTeX Project and any individual authors listed elsewhere
 in this file.
 
diff --git a/macros/latex/required/tools/multicol.pdf b/macros/latex/required/tools/multicol.pdf
index 0295b9ab59..b3d165838a 100644
--- a/macros/latex/required/tools/multicol.pdf
+++ b/macros/latex/required/tools/multicol.pdf
diff --git a/macros/latex/required/tools/rawfonts.dtx b/macros/latex/required/tools/rawfonts.dtx
index 4b930f3ea7..3ffa2032c3 100644
--- a/macros/latex/required/tools/rawfonts.dtx
+++ b/macros/latex/required/tools/rawfonts.dtx
@@ -1,6 +1,6 @@
 % \iffalse meta-comment
 %
-% Copyright (C) 1993-2023
+% Copyright (C) 1993-2024
 %
 % The LaTeX Project and any individual authors listed elsewhere
 % in this file.
diff --git a/macros/latex/required/tools/rawfonts.pdf b/macros/latex/required/tools/rawfonts.pdf
index 2371e70bd6..ab2b851ab6 100644
--- a/macros/latex/required/tools/rawfonts.pdf
+++ b/macros/latex/required/tools/rawfonts.pdf
diff --git a/macros/latex/required/tools/shellesc.dtx b/macros/latex/required/tools/shellesc.dtx
index aa707fe550..8a556de922 100644
--- a/macros/latex/required/tools/shellesc.dtx
+++ b/macros/latex/required/tools/shellesc.dtx
@@ -1,6 +1,6 @@
 % \iffalse
 %% Source File: shellesc.dtx
-%% Copyright (C) 2015-2023
+%% Copyright (C) 2015-2024
 %%
 %% The LaTeX Project and any individual authors listed elsewhere
 %% in this file.
diff --git a/macros/latex/required/tools/shellesc.pdf b/macros/latex/required/tools/shellesc.pdf
index e40b2a84b6..10ad7eb112 100644
--- a/macros/latex/required/tools/shellesc.pdf
+++ b/macros/latex/required/tools/shellesc.pdf
diff --git a/macros/latex/required/tools/showkeys-2014-10-28.sty b/macros/latex/required/tools/showkeys-2014-10-28.sty
index b4d7b19028..9f465dff5c 100644
--- a/macros/latex/required/tools/showkeys-2014-10-28.sty
+++ b/macros/latex/required/tools/showkeys-2014-10-28.sty
@@ -1,4 +1,8 @@
 %%
+%% This is an old release of `showkeys.sty' used during rollback operations.
+%% Do not use this file directly.
+%% ==============================
+%%
 %% This is file `showkeys.sty',
 %% generated with the docstrip utility.
 %%
diff --git a/macros/latex/required/tools/showkeys.dtx b/macros/latex/required/tools/showkeys.dtx
index c90b3863e1..b6717950a7 100644
--- a/macros/latex/required/tools/showkeys.dtx
+++ b/macros/latex/required/tools/showkeys.dtx
@@ -1,6 +1,6 @@
 % \iffalse meta-comment
 %
-% Copyright (C) 1993-2023
+% Copyright (C) 1993-2024
 %
 % The LaTeX Project and any individual authors listed elsewhere
 % in this file.
@@ -22,16 +22,15 @@
 % \fi
 % \iffalse
 %% File: showkeys.dtx Copyright (C) 1992-1997 David Carlisle
-%% File: showkeys.dtx Copyright (C) 2006-2019 David Carlisle, LaTeX Project
+%% File: showkeys.dtx Copyright (C) 2006-2024 David Carlisle, LaTeX Project
 %
 %<*dtx>
           \ProvidesFile{showkeys.dtx}
 %</dtx>
 %<package>\NeedsTeXFormat{LaTeX2e}
 %<package>
-%<package>\providecommand\DeclareRelease[3]{}
-%<package>\providecommand\DeclareCurrentRelease[2]{}
-%<package>
+% For every rollback request before 2022 use the 2014 version:
+%<package>\DeclareRelease{}{1994-06-01}{showkeys-2014-10-28.sty}
 %<package>\DeclareRelease{}{2014-10-28}{showkeys-2014-10-28.sty}
 %<package>\DeclareCurrentRelease{}{2022-06-01}
 %<package>
@@ -39,7 +38,7 @@
 %<driver> \ProvidesFile{showkeys.drv}
 % \fi
 %         \ProvidesFile{showkeys.dtx}
-          [2023/07/08 v3.19 Show cite and label keys (DPC, MH)]
+          [2024/05/23 v3.21 Show cite and label keys (DPC, MH)]
 %
 % \iffalse
 %<*driver>
@@ -417,6 +416,8 @@
 %    \end{macrocode}
 % \changes{v3.02}{1995/03/17}
 %         {New code for `in label' case.}
+% \changes{v3.20}{2023/12/16}
+%         {Avoid adding an extra box layer github/1123}
 % If the |\label| is straight after |\item| (|\bibitem| is handled by
 % this case as well) then the item label has not been added to the page
 % yet. It is hanging around in the box |\@labels| waiting for the
@@ -425,7 +426,7 @@
       \global\setbox\@labels\hbox{%
         \llap{\SK@lab\SK@lab@relax
               \kern\@totalleftmargin\kern\marginparsep}%
-        \box\@labels}%
+        \unhbox\@labels}%
 %    \end{macrocode}
 %
 %    \begin{macrocode}
diff --git a/macros/latex/required/tools/showkeys.pdf b/macros/latex/required/tools/showkeys.pdf
index 7b64f00dea..fb1bc5a5aa 100644
--- a/macros/latex/required/tools/showkeys.pdf
+++ b/macros/latex/required/tools/showkeys.pdf
diff --git a/macros/latex/required/tools/somedefs.dtx b/macros/latex/required/tools/somedefs.dtx
index 02653a1393..156621d70e 100644
--- a/macros/latex/required/tools/somedefs.dtx
+++ b/macros/latex/required/tools/somedefs.dtx
@@ -1,6 +1,6 @@
 % \iffalse meta-comment
 %
-% Copyright (C) 1993-2023
+% Copyright (C) 1993-2024
 %
 % The LaTeX Project and any individual authors listed elsewhere
 % in this file.
diff --git a/macros/latex/required/tools/somedefs.pdf b/macros/latex/required/tools/somedefs.pdf
index 45c79ac29b..0ef55a179e 100644
--- a/macros/latex/required/tools/somedefs.pdf
+++ b/macros/latex/required/tools/somedefs.pdf
diff --git a/macros/latex/required/tools/tabularx.dtx b/macros/latex/required/tools/tabularx.dtx
index 6d59ca4c22..52ee62cad9 100644
--- a/macros/latex/required/tools/tabularx.dtx
+++ b/macros/latex/required/tools/tabularx.dtx
@@ -1,6 +1,6 @@
 % \iffalse meta-comment
 %
-% Copyright (C) 1993-2023
+% Copyright (C) 1993-2024
 %
 % The LaTeX Project and any individual authors listed elsewhere
 % in this file.
@@ -31,7 +31,7 @@
 %<driver> \ProvidesFile{tabularx.drv}
 % \fi
 %         \ProvidesFile{tabularx.dtx}
-          [2023/07/08 v2.11c `tabularx' package (DPC)]
+          [2023/12/11 v2.12a `tabularx' package (DPC)]
 % \iffalse
 %<*driver>
 \documentclass{ltxdoc}
@@ -261,6 +261,25 @@
 % This behaviour of the package can be customised slightly
 % as noted in the documentation of the code section.
 %
+% \section{Support for tagged PDF}
+%
+% With version 2.12a the package is made tagging aware, which means that
+% it will automatically produce tagged tables (necessary, for example, for
+% accessibility) if tagging is requested via \cs{DocumentMetadata}.
+%
+% More granular control, e.g., explicitly deciding which cells are
+% header cells, etc., is currently under development, but syntax for
+% this will not appear in this package. Instead it will become
+% available across all tabular-generating packages and then
+% automatically apply here as well.
+%
+% Enabling \LaTeX{} to automatically produce tagged PDF is a long-term
+% project and this is a tiny step in this puzzle. For more information
+% on the project and already available functionality, see
+% \url{https://latex-project.org/publications/indexbytopic/pdf} and
+% \url{https://github.com/latex3/tagging-project}.
+%
+%
 % \MaybeStop{}
 %
 % \section{The Macros}
@@ -269,6 +288,14 @@
 %<*package>
 %    \end{macrocode}
 %
+%    We only need two changes for tagging support, but they require
+%    that a recent \LaTeX{} kernel is used (which should be no problem
+%    if \texttt{tools} is distributed in parallel with the kernel.
+% \changes{v2.12a}{2023/12/11}{Require newer LaTeX kernel}
+%    \begin{macrocode}
+\NeedsTeXFormat{LaTeX2e}[2024/06/01]
+%    \end{macrocode}
+%
 % \changes{v2.00}{1994/02/07}
 %    {New Option Handling}
 %    \begin{macrocode}
@@ -506,7 +533,15 @@
 %    \begin{macrocode}
   \TX@typeout@
     {\@spaces Table Width\@spaces Column Width\@spaces X Columns}%
-%    \end{macrocode}%
+%    \end{macrocode}
+%
+%    While we do trial typesetting we suspend any tagging if that is
+%    active:
+% \changes{v2.12a}{2023/12/11}
+%    {Suspend any tagging while doing trial typesetting}
+%    \begin{macrocode}
+   \SuspendTagging {tabularx}%
+%    \end{macrocode}
 % First attempt. Modify the {\ttfamily X} definition to count {\ttfamily
 % X} columns.
 %    \begin{macrocode}
@@ -523,6 +558,12 @@
     \TX@trial{}%
   \repeat
 %    \end{macrocode}
+%
+%    And here we restart it again:
+%    \begin{macrocode}
+  \ResumeTagging {tabularx}%
+%    \end{macrocode}
+%
 % One last time, with warnings back on (see appendix D)
 % use {\ttfamily tabular*} to put it in a box of the right size, in case
 % the algorithm failed to find the correct size.
@@ -737,8 +778,9 @@
 % Make the table, and finish the hbox.
 % Since v1.06, "\toks@" contains the preamble specification,
 % and possible optional argument, as well as the table body.
+%    
 %    \begin{macrocode}
-    \expandafter\tabular\the\toks@
+   \expandafter\tabular\the\toks@
     \endtabular}%
 %    \end{macrocode}
 % Since v1.05 reset all \LaTeX\ counters, by executing "\TX@ckpt".
@@ -961,6 +1003,7 @@
 %    \end{macrocode}
 % \end{macro}
 %
+%
 %    \begin{macrocode}
 %</package>
 %    \end{macrocode}
diff --git a/macros/latex/required/tools/tabularx.ins b/macros/latex/required/tools/tabularx.ins
index 6e81e93432..fdce598d37 100644
--- a/macros/latex/required/tools/tabularx.ins
+++ b/macros/latex/required/tools/tabularx.ins
@@ -3,7 +3,7 @@
 %% driver files from the doc files in this package when run through
 %% LaTeX or TeX.
 %%
-%% Copyright (C) 1993-2023
+%% Copyright (C) 1993-2024
 %% The LaTeX Project and any individual authors listed elsewhere
 %% in this file.
 %%
@@ -45,7 +45,7 @@ The source is maintained by the LaTeX Project team and bug
 reports for it can be opened at https://latex-project.org/bugs/
 (but please observe conditions on bug reports sent to that address!)
 
-Copyright (C) 1993-2023
+Copyright (C) 1993-2024
 The LaTeX Project and any individual authors listed elsewhere
 in this file.
 
diff --git a/macros/latex/required/tools/tabularx.pdf b/macros/latex/required/tools/tabularx.pdf
index 5d34197bd2..14c5977f7d 100644
--- a/macros/latex/required/tools/tabularx.pdf
+++ b/macros/latex/required/tools/tabularx.pdf
diff --git a/macros/latex/required/tools/theorem.dtx b/macros/latex/required/tools/theorem.dtx
index e3a8e90b8c..a9c3ccae3e 100644
--- a/macros/latex/required/tools/theorem.dtx
+++ b/macros/latex/required/tools/theorem.dtx
@@ -1,6 +1,6 @@
 % \iffalse meta-comment
 %
-% Copyright (C) 1993-2023
+% Copyright (C) 1993-2024
 %
 % The LaTeX Project and any individual authors listed elsewhere
 % in this file.
diff --git a/macros/latex/required/tools/theorem.pdf b/macros/latex/required/tools/theorem.pdf
index a2bdfebbf8..579c3b0db3 100644
--- a/macros/latex/required/tools/theorem.pdf
+++ b/macros/latex/required/tools/theorem.pdf
diff --git a/macros/latex/required/tools/tools-overview.pdf b/macros/latex/required/tools/tools-overview.pdf
index b4278ab9cd..a17f776df9 100644
--- a/macros/latex/required/tools/tools-overview.pdf
+++ b/macros/latex/required/tools/tools-overview.pdf
diff --git a/macros/latex/required/tools/tools-overview.tex b/macros/latex/required/tools/tools-overview.tex
index 3bc325d67c..54f4b5ed63 100644
--- a/macros/latex/required/tools/tools-overview.tex
+++ b/macros/latex/required/tools/tools-overview.tex
@@ -1,7 +1,7 @@
 \NeedsTeXFormat{LaTeX2e}
 \ProvidesFile{tools-overview.tex}[2015/03/31 v1.0 Tools overview]
 
-% Copyright (C) 2006-2023
+% Copyright (C) 2006-2024
 %
 % The LaTeX Project and any individual authors listed elsewhere
 % in this file.
diff --git a/macros/latex/required/tools/tools.ins b/macros/latex/required/tools/tools.ins
index 6898faead3..8687d49d7f 100644
--- a/macros/latex/required/tools/tools.ins
+++ b/macros/latex/required/tools/tools.ins
@@ -3,7 +3,7 @@
 %% driver files from the doc files in this package when run through
 %% LaTeX or TeX.
 %%
-%% Copyright (C) 1993-2023
+%% Copyright (C) 1993-2024
 %% The LaTeX Project and any individual authors listed elsewhere
 %% in this file.
 %%
@@ -49,7 +49,7 @@ reports for it can be opened at https://latex-project.org/bugs/
 (but please observe conditions on bug reports sent to that address!)
 
 
-Copyright (C) 1993-2023
+Copyright (C) 1993-2024
 The LaTeX Project and any individual authors listed elsewhere
 in this file.
 
@@ -178,6 +178,13 @@ given in the file `manifest.txt'.
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \SimplePackage{shellesc}
 
+
+% Shell Filee System Queries
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\batchinput{l3sys-query.ins}
+
+
+
 % File-Error files
 %%%%%%%%%%%%%%%%%%
 \generate{%
diff --git a/macros/latex/required/tools/trace.dtx b/macros/latex/required/tools/trace.dtx
index 788f831620..27a39c776b 100644
--- a/macros/latex/required/tools/trace.dtx
+++ b/macros/latex/required/tools/trace.dtx
@@ -1,6 +1,6 @@
 % \iffalse meta-comment
 %
-% Copyright (C) 1993-2023
+% Copyright (C) 1993-2024
 %
 % The LaTeX Project and any individual authors listed elsewhere
 % in this file.
diff --git a/macros/latex/required/tools/trace.pdf b/macros/latex/required/tools/trace.pdf
index 34050d5f22..7b57ee0ea7 100644
--- a/macros/latex/required/tools/trace.pdf
+++ b/macros/latex/required/tools/trace.pdf
diff --git a/macros/latex/required/tools/varioref-2016-02-16.sty b/macros/latex/required/tools/varioref-2016-02-16.sty
index 747e89dc60..39cc4467a7 100644
--- a/macros/latex/required/tools/varioref-2016-02-16.sty
+++ b/macros/latex/required/tools/varioref-2016-02-16.sty
@@ -1,4 +1,8 @@
 %%
+%% This is an old release of `varioref.sty' used during rollback operations.
+%% Do not use this file directly.
+%% ==============================
+%%
 %% This is file `varioref.sty',
 %% generated with the docstrip utility.
 %%
diff --git a/macros/latex/required/tools/varioref.dtx b/macros/latex/required/tools/varioref.dtx
index e801c54f81..40b3038074 100644
--- a/macros/latex/required/tools/varioref.dtx
+++ b/macros/latex/required/tools/varioref.dtx
@@ -1,6 +1,6 @@
 % \iffalse meta-comment
 %
-% Copyright (C) 1993-2023
+% Copyright (C) 1993-2024
 %
 % The LaTeX Project and any individual authors listed elsewhere
 % in this file.
@@ -33,14 +33,15 @@
 %%
 %
 %<package>\NeedsTeXFormat{LaTeX2e}[1995/05/16]
-%<package>\providecommand\DeclareRelease[3]{}
-%<package>\providecommand\DeclareCurrentRelease[2]{}
 %<package>
+%
+% For any rollback before 2019 load the 2016 version and hope for the best:
+%<package>\DeclareRelease{}{1994-06-01}{varioref-2016-02-16.sty}
 %<package>\DeclareRelease{}{2016-02-16}{varioref-2016-02-16.sty}
 %<package>\DeclareCurrentRelease{}{2019-10-01}
 %<package>
 %<package>\ProvidesPackage{varioref}
-%<package>    [2022/01/09 v1.6f package for extended references (FMi)]
+%<package>    [2024/05/23 v1.6g package for extended references (FMi)]
 % \fi
 %
 %%
@@ -144,8 +145,8 @@
 %\DescribeMacro\vref The implementation of |\vref| below produces only
 % a |\ref| when reference and |\label| are on the same page. It will
 % additionally produce one of the strings `on the facing page', `on
-% the preceding page', or `on the following page', if label and
-% reference differ by one and it will produce both |\ref| and
+% the preceding page', or `on the following page' if label and
+% reference differ by one; and it will produce both |\ref| and
 % |\pageref| when the difference is larger.  The word `facing' is used
 % when label and reference both fall onto a double spread.  However,
 % if a special page numbering scheme is used instead of the usual
@@ -169,7 +170,7 @@
 % comes out as ``\ldots~see the example which shows~\ldots'', which
 % could be misleading.
 %
-% A space in front of |\vpageref| it will be ignored if
+% A space in front of |\vpageref| will be ignored if
 % the command doesn't produce any text at all.
 %
 % But in fact |\vpageref| allows even more control. It has two
@@ -210,7 +211,7 @@
 % \DescribeMacro\vrefrange
 % This command is similar to |\vref| but it
 % takes two mandatory arguments denoting a range to refer to (e.g., a
-% sequences of figures or a sequence of equations, etc.). So if
+% sequence of figures or a sequence of equations, etc.). So if
 % |fig:a| is your first figure in the sequence and |fig:c| your last
 % you can write
 %\begin{verbatim}
@@ -273,8 +274,8 @@
 % \DescribeMacro\vpagerefcompare
 % \NewIn{2019}
 % For this kind of application the package also provides
-% |\vpagerefcompare| as a command that takes four argument: two labels for
-% comparison and a \meta{true} and \meta{false} argument. One of them
+% |\vpagerefcompare| as a command that takes four arguments: two labels
+% for comparison and a \meta{true} and \meta{false} argument. One of them
 % is executed depending on whether the two labels are on the same page
 % or on different pages. With its help the above definition could be
 % shortened to
@@ -293,8 +294,9 @@
 % Another command for conditional processing is |\vpagerefnearby|. It
 % takes three arguments: a label and a \meta{true} and \meta{false}
 % argument. It compares the page reference to the label with the
-% current page number and if both are Arabic number and only differ by
-% $\pm1$ the \meta{true} argument is executed otherwise the
+% current page number; if each of these is a positive integer
+% (expressed in Arabic numerals) and they differ by at most
+% $\pm1$, the \meta{true} argument is executed, otherwise the
 % \meta{false} argument. In other words it tells you if a |\vpageref|
 % to the label would result in a textual reference to the previous,
 % current or next page.\footnote{There is also a
@@ -320,11 +322,11 @@
 % versions of the macros which do not add any space before the
 % generated text (they do nevertheless remove space at the left).
 %
-% However, that too has problems (one is that \pkg{hyperref}
+% However, that too has problems: one is that \pkg{hyperref}
 % \ChangedIn{2019}
-% introduced the star forms as a means to generating references
-% without hyperlinks (which is clearly the more important
-% application).
+% introduced the star forms as a means of generating references
+% without hyperlinks, which is clearly the more important
+% application.
 % So these days I recommend to always call the package with the option
 % \option{nospace} which prevents \pkg{varioref} from messing with the
 % space in front. Of course you are then responsible to always add it
@@ -381,7 +383,7 @@
 % label and reference fall onto the same page, but prefer reference to
 % page numbers otherwise then |\thevpagerefnum| can be used. This macro
 % hold the current page ``number'' when |\vpageref| and friends are
-% executed. Thus, by defining, for example
+% executed. Thus, by defining, for example,
 %\begin{verbatim}
 %\renewcommand\reftextfaceafter {on page~\thevpagerefnum}
 %\renewcommand\reftextfacebefore{on page~\thevpagerefnum}
@@ -436,7 +438,7 @@
 %\DescribeMacro\reftextafter
 %\DescribeMacro\reftextfaceafter Backward references use
 % |\reftextbefore| if the label is on the preceding page but invisible
-% and |\reftextfacebefore| if it is one the facing page (i.e., if the
+% and |\reftextfacebefore| if it is on the facing page (i.e., if the
 % current page number is odd).  Similarly |\reftextafter| is used
 % when the label comes on the next page but one has to turn the page
 % and |\reftextfaceafter| if it is on the following but facing page.
@@ -447,7 +449,7 @@
 %\DescribeMacro\reftextfaraway Finally we have |\reftextfaraway| which
 % is used whenever label and reference differ by more than one or when
 % they aren't numeric. This macro is a bit different because it takes
-% one argument, the symbolic reference string so that one cane make
+% one argument, the symbolic reference string, so that one can make
 % use of |\pageref| in its replacement text.
 %
 %
@@ -521,7 +523,7 @@
 % and \option{nospace}. While the former is the default to allow
 % \NewIn{2019}
 % documents written in the last twenty years to continue to work
-% correctly, I nowadays, suggest that you always use the package with
+% correctly, I nowadays suggest that you always use the package with
 % the option \option{nospace}. This will stop \pkg{varioref} from
 % meddling with the spaces preceding commands and thus make the star
 % forms |\vref*| and |\vpageref*| unnecessary.
@@ -536,7 +538,7 @@
 % Defining commands like the ones described above poses some
 % interesting problems. Suppose, for example, that a generated text
 % like `on the next page' gets broken across pages. If this happens it
-% is very difficult to find an acceptable solution and in fact can
+% is very difficult to find an acceptable solution and it can, in fact,
 % even result in a document that will always change from one state to
 % another (i.e., inserting one string, finding that this is wrong,
 % inserting another string on the next run which makes the first
@@ -699,7 +701,7 @@
 %  \begin{macro}{\reftextbefore}
 %  \begin{macro}{\reftextcurrent}
 % \label{reftextbefore} The options do set the macros that
-%    generate the textual strings. Note, that they do not start with a
+%    generate the textual strings. Note that they do not start with a
 %    space, the space is already added in the main macro below.
 % \changes{v1.2a}{1998/08/22}{Added American defaults for
 %      \cs{reftextpagerange} and \cs{reftextlabelrange}}
@@ -838,7 +840,7 @@
 %    the noun (clause); bertentangan is ``opposite'' in the sense of
 %    ``facing''; berikutnya is ``next'' (in this context - actually
 %    next-to-this, literally); berikutnya also translates as ``following
-%    this'' sebelumnya is ``preceding''; also ``previous'' ``ini'' translates,
+%    this''; sebelumnya is ``preceding'', also ``previous''; ``ini'' translates,
 %    literally, as ``this'' but is also used in the sense of current page.
 % \changes{v1.4o}{2005/12/02}{Bahasa Malaysia defaults added.}
 %    \begin{macrocode}
@@ -1036,7 +1038,7 @@
     \let\vrefrangeformat\vrefrangedefaultformat
   }}
 %    \end{macrocode}
-%    Default string for dutch have been contributed by Frank Poppe
+%    Default strings for Dutch have been contributed by Frank Poppe
 %    (\verb=POPPE@SWOV.NL=).
 %    This option currently supports one additional string macro
 %    |\refpagename| so that you can easily change to |bladzijde|
@@ -1124,9 +1126,9 @@
     \let\vrefrangeformat\vrefrangedefaultformat
   }}
 %    \end{macrocode}
-%    The finnish strings were suggested by Matti Rintala
+%    The Finnish strings were suggested by Matti Rintala
 %    (\verb=bitti@cs.tut.fi=) and Hillevi Gavel
-%    \verb=Hillevi.Gavel@mdh.se=.
+%    (\verb=Hillevi.Gavel@mdh.se=).
 % \changes{v1.0m}{1994/09/23}{Added finnish strings}
 % \changes{v1.4o}{2005/11/07}{Added a few more finnish strings}
 %    \begin{macrocode}
@@ -1200,10 +1202,10 @@
   }}
 %    \end{macrocode}
 %    There are no good variants for German (I think and still think but
-%    this is a matter of taste :-).
+%    this is a matter of taste :-)).
 % \changes{v1.0b}{1994/01/31}{Replace in incorrect `def by `let}
 %    The following definitions were recently suggested to me but since
-%    the original are in for a long time i don't want to change them
+%    the originals have been there for a long time I don't want to change them
 %    now since that could make a lot of documents change their formatting.
 %    If you fancy them, add a redefinition of the corresponding macro(s)
 %    to the preamble of your document.
@@ -1935,7 +1937,7 @@
 %    \end{macrocode}
 %    But if \texttt{nospace} is in force we simply use the same space
 %    value that was used in the source document (unless that was zero
-%    or non-existent.
+%    or non-existent).
 %    \begin{macrocode}
     \ifdim\@tempskipa=\z@ \else
       \hskip\@tempskipa
@@ -1978,7 +1980,7 @@
 %    \begin{macrocode}
   \vrefpagenum\thevpagerefnum{#3}%
 %    \end{macrocode}
-%    Now after the internal label has served its purpose if would be
+%    Now after the internal label has served its purpose it would be
 %    nice to free the memory it occupies by using something like
 %    \begin{verbatim}
 % \global\expandafter\let
@@ -2008,7 +2010,7 @@
     \fi
   \else
 %    \end{macrocode}
-%    If |#2| is empty we do nothing otherwise we insert it followed by
+%    If |#2| is empty we do nothing, otherwise we insert it followed by
 %    a space.
 %    \begin{macrocode}
     \def\@tempc{#2}%
@@ -2017,7 +2019,7 @@
     \fi
 %    \end{macrocode}
 %    Now we check if the page number of the referenced object (stored
-%    in |\thevpagerefnum| is a single positive number.
+%    in |\thevpagerefnum|) is a single positive number.
 %    \begin{macrocode}
     \is@pos@number\thevpagerefnum
        {%
@@ -2032,7 +2034,7 @@
          }%
 %    \end{macrocode}
 %    If it is not a positive number we assign the largest possible
-%    number to |\@tempcnta| and thereby pretending that label and
+%    number to |\@tempcnta|, thereby pretending that label and
 %    reference are miles away from each other.
 %    \begin{macrocode}
          {\@tempcnta\maxdimen}%
@@ -2049,7 +2051,7 @@
 %    Thus if the object falls onto an odd page then the reference is
 %    on the facing even page (and so we insert |\reftextfaceafter|),
 %    otherwise the object can not be seen from the reference (and we
-%    in insert |\reftextafter|).  Don't be surprised if we are not
+%    insert |\reftextafter|).  Don't be surprised if we are not
 %    using |\thevpagerefnum| in the check. Since |\@tempcnta| has the same
 %    value it is faster to use the register instead of parsing the
 %    macro contents anew.
@@ -2061,7 +2063,7 @@
 %    used.
 %    Since the value of |\if@twoside| is evaluated before reading in
 %    packages we could do better (saving some tokens) by defining
-%    the current macro in dependence of this boolean.
+%    the current macro depending on this boolean.
 %    \begin{macrocode}
            \if@twoside
              \reftextfaceafter
@@ -2075,11 +2077,11 @@
 %    If the object is not on the page following the reference we check
 %    if it is on the page before the reference. In \LaTeX{} this
 %    situation is not too common, for example with floats it normally
-%    does not occur, but of course it isn't impossible if you more
+%    does not occur, but of course it isn't impossible if you have more
 %    than one reference to the same object, or if you have back
 %    references to sections, theorems, etc.  To test this we now
 %    subtract two from the current value of |\@tempcnta| (which was
-%    set to one higher as the reference page number). Note, that
+%    set to one higher as the reference page number). Note that
 %    subtraction is also possible if the value was |\maxdimen| --- we
 %    still get something that is much larger than any sensible page
 %    number.
@@ -2131,7 +2133,7 @@
          \reftextfaraway{#3}}%
   \fi
 %    \end{macrocode}
-%    Finally we generate the internal label so that it can be check on
+%    Finally, we generate the internal label so that it can be checked on
 %    the next run. This means that we compare the position after the
 %    string with the position of the referenced object. There is one
 %    thing to note: to conserve space we locally make |\@currentlabel|
@@ -2252,8 +2254,8 @@
 %    The star form is easy (and just a convenient shortcut), just call
 %    |\ref| followed by |\vpageref| and pass the optional argument to
 %    the latter. We don't support the second optional argument of
-%    |\vpageref|, it that is needed one has to call both commands
-%    explicitly
+%    |\vpageref|, if that is needed one has to call both commands
+%    explicitly.
 % \changes{v1.6a}{2019/08/25}{Command added to support hyperref better}
 % \changes{v1.6e}{2020/07/25}{Changed for Japanese (gh/352)}
 %    \begin{macrocode}
@@ -2264,7 +2266,7 @@
 %
 %  \begin{macro}{\vrefformat,\vrefdefaultformat}
 %    Japanese needs a different word order in \cs{vref@star} so this
-%    is separated out o that it can be changed on language level.
+%    is separated out so that it can be changed at the language level.
 % \changes{v1.6e}{2020/07/25}{Macro added (gh/352)}
 %    \begin{macrocode}
 \def\vrefdefaultformat#1#2{% 
@@ -2293,7 +2295,7 @@
     \unskip \nobreakspace
   \fi
 %    \end{macrocode}
-%    The use of|\nobreakspace| or |~| after the |\unskip| means that
+%    The use of |\nobreakspace| or |~| after the |\unskip| means that
 %    this command will always produce a normal space while
 %    something like |\nobreak\space| will
 %    react to settings of |\nonfrenchspacing|.
@@ -2341,10 +2343,10 @@
 %    Now we have to check whether or not the whole string was parsed
 %    into that register or some remainder was left over. Since we have
 %    added a |\@nil| token at the very end we can use that to delimit
-%    the argument of |\is@pos@num@|. Note, that the added space in
+%    the argument of |\is@pos@num@|. Note that the added space in
 %    |\is@pos@number| \vpageref[above]{isposnumber} gets parsed away
 %    by the counter assignment. If it would be missing, and the full
-%    string would consist of a number, \TeX{}would try to replace
+%    string would consist of a number, \TeX{} would try to replace
 %    |\@nil| by its definition to see if it would contain additional
 %    digits and thus we would be in trouble at this point.
 %    \begin{macrocode}
@@ -2389,7 +2391,7 @@
 %
 %  \begin{macro}{\fullrefformat,\fullrefdefaultformat}
 %    Japanese needs a different word order in \cs{fullref}  so this
-%    is separated out o that it can be changed on language level.
+%    is separated out so that it can be changed at the language level.
 % \changes{v1.6e}{2020/07/25}{Macro added (gh/352)}
 %    \begin{macrocode}
 \def\fullrefdefaultformat#1{% 
@@ -2523,7 +2525,7 @@
 %
 %  \begin{macro}{\vrefrangeformat,\vrefrangedefaultformat}
 %    Japanese needs a different word order in \cs{vrefrange}  so this
-%    is separated out o that it can be changed on language level.
+%    is separated out so that it can be changed at the language level.
 % \changes{v1.6d}{2020/07/20}{Macro added (gh/352)}
 %    \begin{macrocode}
 \def\vrefrangedefaultformat#1#2#3{% 
@@ -2558,7 +2560,7 @@
 %
 %  \begin{macro}{\Vrefformat,\Vrefdefaultformat}
 %    Japanese needs a different word order in \cs{Vref}  so this
-%    is separated out o that it can be changed on language level.
+%    is separated out so that it can be changed at the language level.
 % \changes{v1.6e}{2020/07/25}{Macro added (gh/352)}
 %    \begin{macrocode}
 \def\Vrefdefaultformat#1#2{% 
diff --git a/macros/latex/required/tools/varioref.ins b/macros/latex/required/tools/varioref.ins
index dcc41d0176..88527a20ba 100644
--- a/macros/latex/required/tools/varioref.ins
+++ b/macros/latex/required/tools/varioref.ins
@@ -3,7 +3,7 @@
 %% driver files from the doc files in this package when run through
 %% LaTeX or TeX.
 %%
-%% Copyright (C) 1993-2023
+%% Copyright (C) 1993-2024
 %% The LaTeX Project and any individual authors listed elsewhere
 %% in this file.
 %%
@@ -45,7 +45,7 @@ The source is maintained by the LaTeX Project team and bug
 reports for it can be opened at https://latex-project.org/bugs/
 (but please observe conditions on bug reports sent to that address!)
 
-Copyright (C) 1993-2023
+Copyright (C) 1993-2024
 The LaTeX Project and any individual authors listed elsewhere
 in this file.
 
diff --git a/macros/latex/required/tools/varioref.pdf b/macros/latex/required/tools/varioref.pdf
index 64c89e6f49..7a5aa90622 100644
--- a/macros/latex/required/tools/varioref.pdf
+++ b/macros/latex/required/tools/varioref.pdf
diff --git a/macros/latex/required/tools/verbatim.dtx b/macros/latex/required/tools/verbatim.dtx
index ebcc010a80..468dead3e8 100644
--- a/macros/latex/required/tools/verbatim.dtx
+++ b/macros/latex/required/tools/verbatim.dtx
@@ -1,6 +1,6 @@
 % \iffalse meta-comment
 %
-% Copyright (C) 1993-2023
+% Copyright (C) 1993-2024
 %
 % The LaTeX Project and any individual authors listed elsewhere
 % in this file.
@@ -69,6 +69,8 @@
 %\fi
 %
 %
+% 
+% \changes{v1.5x}{2024/01/22}{Added TAB marking support to \cs{verbatiminput*}}
 % \changes{v1.5u}{2020-07-07}{Typo repair and added a missing comment
 %    character}
 % \changes{v1.5q}{2003/08/22}{Reintroduced \cs{@noligs}, by popular
@@ -508,7 +510,7 @@
 %<*package>
 \NeedsTeXFormat{LaTeX2e}
 \ProvidesPackage{verbatim}
-     [2023-11-06 v1.5v LaTeX2e package for verbatim enhancements]
+     [2024-01-22 v1.5x LaTeX2e package for verbatim enhancements]
 \@ifundefined{verbatim@@@}{}{\endinput}
 %    \end{macrocode}
 %
@@ -1570,7 +1572,14 @@
 %    arguments, depending on whether an asterisk follows.
 %    \begin{macrocode}
 \def\verbatiminput{\begingroup
-  \@ifstar{\verbatim@input\relax}%
+%    \end{macrocode}
+% 
+%   \changes{v1.5x}{2024/01/22}{Added TAB marking support into the
+%   starred version (gh/1245)}
+%   If starred, we mark spaces and TABs, the two
+%   added pieces are the same as for verbatim*.
+%    \begin{macrocode}
+  \@ifstar{\verbatim@input{\@setupverbvisiblespace\@vobeyspaces}}%
           {\verbatim@input{\frenchspacing\@vobeyspaces}}}
 %    \end{macrocode}
 % \end{macro}
diff --git a/macros/latex/required/tools/verbatim.pdf b/macros/latex/required/tools/verbatim.pdf
index a8238cf344..65e18697f4 100644
--- a/macros/latex/required/tools/verbatim.pdf
+++ b/macros/latex/required/tools/verbatim.pdf
diff --git a/macros/latex/required/tools/xr-2023-07-04.sty b/macros/latex/required/tools/xr-2023-07-04.sty
new file mode 100644
index 0000000000..15bfde169a
--- /dev/null
+++ b/macros/latex/required/tools/xr-2023-07-04.sty
@@ -0,0 +1,84 @@
+%%
+%% This is an old release of `xr.sty' used during rollback operations.
+%% Do not use this file directly.
+%% ==============================
+%%
+%% This is file `xr.sty',
+%% generated with the docstrip utility.
+%%
+%% The original source files were:
+%%
+%% xr.dtx  (with options: `package')
+%% 
+%% This is a generated file.
+%% 
+%% The source is maintained by the LaTeX Project team and bug
+%% reports for it can be opened at https://latex-project.org/bugs/
+%% (but please observe conditions on bug reports sent to that address!)
+%% 
+%% 
+%% Copyright (C) 1993-2023
+%% The LaTeX Project and any individual authors listed elsewhere
+%% in this file.
+%% 
+%% This file was generated from file(s) of the Standard LaTeX `Tools Bundle'.
+%% --------------------------------------------------------------------------
+%% 
+%% It may be distributed and/or modified under the
+%% conditions of the LaTeX Project Public License, either version 1.3c
+%% of this license or (at your option) any later version.
+%% The latest version of this license is in
+%%    https://www.latex-project.org/lppl.txt
+%% and version 1.3c or later is part of all distributions of LaTeX
+%% version 2005/12/01 or later.
+%% 
+%% This file may only be distributed together with a copy of the LaTeX
+%% `Tools Bundle'. You may however distribute the LaTeX `Tools Bundle'
+%% without such generated files.
+%% 
+%% The list of all files belonging to the LaTeX `Tools Bundle' is
+%% given in the file `manifest.txt'.
+%% 
+%% File: xr.dtx Copyright (C) 1993-2019 David Carlisle
+\NeedsTeXFormat{LaTeX2e}
+\ProvidesPackage{xr}
+         [2023-07-04 v5.06 eXternal References (DPC)]
+\def\externaldocument{\@ifnextchar[\XR@{\XR@[]}}
+\let\externalcitedocument\externaldocument
+\def\XR@[#1]#2{{%
+  \makeatletter
+  \def\XR@prefix{#1}%
+  \set@curr@file{#2}%
+  \expandafter\XR@next\@curr@file.aux\relax\\}}
+\def\XR@next#1\relax#2\\{%
+  \edef\XR@list{#2}%
+  \XR@loop{#1}}
+\def\XR@aux{%
+  \ifx\XR@list\@empty\else\expandafter\XR@explist\fi}
+
+\def\XR@explist{\expandafter\XR@next\XR@list\\}
+\def\XR@loop#1{\openin\@inputcheck{#1}\relax
+  \ifeof\@inputcheck
+    \PackageWarning{xr}{^^JNo file #1^^JLABELS NOT IMPORTED.^^J}%
+    \expandafter\XR@aux
+  \else
+    \PackageInfo{xr}{IMPORTING LABELS FROM #1}%
+    \expandafter\XR@read\fi}
+\def\XR@read{%
+  \read\@inputcheck to\XR@line
+  \expandafter\XR@test\XR@line...\XR@}
+\long\def\XR@test#1#2#3#4\XR@{%
+  \let\XR@tempa\@gobbletwo
+  \ifx#1\newlabel
+    \let\XR@tempa\@firstoftwo
+  \else\ifx#1\bibcite
+    \let\XR@tempa\@firstoftwo
+  \else\ifx#1\@input
+     \let\XR@tempa\@secondoftwo
+  \fi\fi\fi
+   \XR@tempa{#1{\XR@prefix#2}{#3}}{\edef\XR@list{\XR@list#2\relax}}%
+  \ifeof\@inputcheck\expandafter\XR@aux
+  \else\expandafter\XR@read\fi}
+\endinput
+%%
+%% End of file `xr.sty'.
diff --git a/macros/latex/required/tools/xr.dtx b/macros/latex/required/tools/xr.dtx
index be48f5a01b..daa0778b36 100644
--- a/macros/latex/required/tools/xr.dtx
+++ b/macros/latex/required/tools/xr.dtx
@@ -1,6 +1,6 @@
 % \iffalse meta-comment
 %
-% Copyright (C) 1993-2023
+% Copyright (C) 1993-2024
 %
 % The LaTeX Project and any individual authors listed elsewhere
 % in this file.
@@ -21,14 +21,49 @@
 %
 % \fi
 % \iffalse
-%% File: xr.dtx Copyright (C) 1993-2019 David Carlisle
+%% File: xr.dtx Copyright (C) 1993-2024 David Carlisle
 %
 %<package>\NeedsTeXFormat{LaTeX2e}
+%<package>\DeclareRelease{v5}{2023-07-04}{xr-2023-07-04.sty}
+%<package>\DeclareCurrentRelease{}{2024-04-10}
 %<package>\ProvidesPackage{xr}
-%<package>         [2023-07-04 v5.06 eXternal References (DPC)]
+%<package>         [2024-04-10 v6.00 eXternal References (DPC)]
 %
 %<*driver>
-\documentclass{ltxdoc}
+\documentclass{l3doc}
+% currently missing in l3doc, copied from array.dtx
+\makeatletter
+\def\MaintainedBy#1{\gdef\@maintainedby{#1}}
+\let\@maintainedby\@empty
+\def\MaintainedByLaTeXTeam#1{%
+{\gdef\@maintainedby{%
+This file is maintained by the \LaTeX{} Project team.\\%
+Bug reports can be opened (category \texttt{#1}) at\\%
+\url{https://latex-project.org/bugs.html}.}}}
+\def\@maketitle{%
+  \newpage
+  \null
+  \vskip 2em%
+  \begin{center}%
+  \let \footnote \thanks
+    {\LARGE \@title \par}%
+    \vskip 1.5em%
+    {\large
+      \lineskip .5em%
+      \begin{tabular}[t]{c}%
+        \@author
+      \end{tabular}\par}%
+    \vskip 1em%
+    {\large \@date}%
+    \ifx\@maintainedby\@empty
+    \else
+    \vskip 1em%
+    \fbox{\fbox{\begin{tabular}{@{}l@{}}\@maintainedby\end{tabular}}}%
+    \fi
+  \end{center}%
+  \par
+  \vskip 1.5em}
+\makeatother
 \usepackage{xr}
 \GetFileInfo{xr.sty}
 \begin{document}
@@ -50,44 +85,113 @@
 %
 % \changes{v5.00}{1993/07/07}
 %         {First DPC version (by agreement with J-PD).  New mechanism
-%         (\cmd{\read} instead of \cmd\input).}
+%         (\cs{read} instead of \cs{input}).}
 %
 % \changes{v5.01}{1993/07/20}{Fix bug added by DPC, v5.00 did not import
-%           aux files of \cmd\include'ed files. (Reported by J-PD)}
+%           aux files of \cs{include}'ed files. (Reported by J-PD)}
 %
 % \changes{v5.02}{1994/05/28}{Update for LaTeX2e}
 % \changes{v5.03}{2018/10/01}{Fix for conditionals in aux file}
 % \changes{v5.05}{2019/07/20}{include xcite}
+% \changes{v6.00}{2024/04/10}{merge with xr-hyper}
 %
 %
 % This package implements a system for eXternal References.
-%
+% Version 6.00 merges the \pkg{xr} package and the \pkg{xr-hyper} package.
+% \pkg{xr-hyper} was developed to support the
+% extended label syntax of the \pkg{hyperref} package and to enable active links
+% to the external documents. 
+% In the \LaTeX{} release 2023-06-01 the label syntax of \pkg{hyperref}
+% and the \LaTeX{} kernel have been synchronized and there is no longer
+% a need for two packages. The package \pkg{xr-hyper} will be 
+% deprecated.
+% 
+% The previous version before the merge can be accessed with 
+% \begin{verbatim}
+% \usepackage{xr}[=v5]
+% \end{verbatim}
+% or with a rollback date between 2023-07-04 and 2024-04-09
+% \begin{verbatim}
+% \usepackage{xr}[=2024-04-09] 
+% \end{verbatim}
+% 
+% \section{Usage}
+% 
+% \begin{syntax}
+% \cs{externaldocument}\oarg{prefix}\texttt[nocite\texttt]\marg{document}\oarg{url}
+% \end{syntax}
+% 
 % If one document needs to refer to sections of another, say |aaa.tex|,
 % then this package may be loaded in the main file, and the command\\
 % |\externaldocument{aaa}|\\
 %  given in the preamble.
 %
-% Then you may use |\ref| and |\pageref| to refer to anything which has
+% Then you may use |\ref| and |\pageref| (or |\nameref| if the
+% package \pkg{nameref} has been loaded to refer to anything which has
 % been given a |\label| in either |aaa.tex| or the main document.
+% It is also possible to refer to properties stored with \cs{RecordProperties}.
 % You may declare any number of such external documents.
 %
 % If any of the external documents, or the main document, use the same
 % |\label| then an error will occur as the label will be multiply
 % defined. To overcome this problem |\externaldocument| has an optional
-% argument. If you declare |\externaldocument[A-]{aaa}|, then all
+% argument \meta{prefix}. 
+% If you declare |\externaldocument[A-]{aaa}|, then all
 % references from |aaa| are prefixed by |A-|. So for instance, if a
 % section of |aaa| had |\label{intro}|, then this could be referenced
 % with |\ref{A-intro}|. The prefix need not be |A-|, it can be any
 % string chosen to ensure that all the labels imported from external
-% files are unique. Note however that if your style declares certain
-% active characters (|:| in French, |"| in German) then these
-% characters can not usually be used in |\label|, and similarly may not
-% be used in the optional argument to |\externaldocument|.
+% files are unique. Note however that the prefix is expanded and
+% so should not contain commands that are not safe in this context. 
 %
 % As first suggested in Enrico Gregorio's |xcite| package, the current version
 % also allows |\cite| to reference |\bibitem| in the external document.
 % For compatibility with |xcite|, |\externalcitedocument| is made available
 % as an alias for |\externaldocument|
+% 
+% Many packages have variant citation commands (natbib,
+% biblatex,....) and the external document may or may not have used
+% hyperref. Because of these differences the citation linking may not
+% always work, it can be disabled by specifying \texttt{[nocite]} after the
+% \meta{prefix}:
+% \begin{verbatim}
+%  \externaldocument[][nocite]{aaa}
+% \end{verbatim}  
+% 
+% The `document' referred to by the main argument \meta{document} is the file
+% \file{document.aux} which must be somewhere on TeX's input path.
+% Some packages (eg hyperref) really need to know the location of the
+% final document rather than the aux file. By default this is assumed
+% to be \file{document.pdf}. A package may redefine the command \cs{XR@ext} to
+% change this default extension. However sometimes the final
+% document may be in a position unrelated to the aux file, or the
+% browser may not be able to find files at an arbitrary point in
+% TeX's input path, so the final optional argument \meta{url} allows a full
+% URL to the final document to be specified.
+% \begin{verbatim}
+% \externaldocument{aaa}[https://example.com/this/path/to/aaa.pdf]
+% \end{verbatim}
+% 
+% The package stores the url of the external document in the label data. It can
+% e.g. be retrieved with the \pkg{refcount} package
+% 
+% \begin{verbatim}
+% \usepackage{refcount,xr}
+% \externaldocument{aaa}
+% ...
+% \getrefbykeydefault{intro}{url}{??} %prints aaa.pdf or ??
+% \end{verbatim}
+% 
+% \pkg{xr} supports also the properties introduced in \LaTeX{} 2023-11-01.
+% Here the url of the external document is stored in the \texttt{xr-url} property.
+% 
+% \begin{verbatim}
+% \usepackage{xr}
+% \externaldocument{aaa} %aaa contains \RecordProperties{intro}{page}
+% ...
+% \RefProperty{intro}{page}   %gives page number
+% \RefProperty{intro}{xr-url} %gives aaa.pdf 
+% \end{verbatim}
 %
 % \MaybeStop{}
 %
@@ -98,20 +202,74 @@
 %    \end{macrocode}
 %
 % Check for the optional argument.
+% \changes{v6.00}{2024-04-10}{Copied over extended definition of xr-hyper}
 %    \begin{macrocode}
-\def\externaldocument{\@ifnextchar[\XR@{\XR@[]}}
+\def\externaldocument{\@testopt\XR@cite{}}
 \let\externalcitedocument\externaldocument
+\def\XR@cite[#1]{\@testopt{\XR@[#1]}{}}
+\def\XR@[#1][#2]#3{\@testopt{\XR@@{#1}{#2}{#3}}{#3.\XR@ext}}
+%    \end{macrocode}
+%
+% \subsection{helper definitions}
+% \changes{v6.00}{2024-04-10}{new, copied over from xr-hyper}
+% To test the second optional argument
+%    \begin{macrocode}
+\def\XR@@nocite{nocite}
+%    \end{macrocode}
+% Needed in the processing
+%    \begin{macrocode}
+\long\def\@gobblefour  #1#2#3#4{}
+\long\def\@firstoffour #1#2#3#4{#1}
+\long\def\@secondoffour#1#2#3#4{#2}
+\long\def\@thirdoffour #1#2#3#4{#3}
+\long\def\@fourthoffour #1#2#3#4{#4}
+%    \end{macrocode}
+% The url is added as fifth argument. The command used here is
+% \cs{XR@addURL}. The command is more complicated as needed
+% as it tries to handle also older documents with 
+% \cs{newlabel}'s with two arguments. 
+%    \begin{macrocode}
+\def\XR@addURL#1{\XR@@dURL#1{}{}{}{}\\}
+\def\XR@@dURL#1#2#3#4#5\\{%
+     \unexpanded{{#1}{#2}{#3}{#4}}{\XR@URL}% 
+  }%
+%    \end{macrocode}
+% 
+% \subsection{Variables}
+% \changes{v6.00}{2024-04-10}{new, copied over from xr-hyper}
+% Default file extension:
+%    \begin{macrocode}
+\providecommand\XR@ext{pdf}
 %    \end{macrocode}
 %
-%    Save the optional prefix. Start processing the first |aux| file.
-%  \changes{v5.06}{2020-05-10}{Remove leading and trailing sapces from
+% Save the optional prefix. Start processing the first |aux| file.
+%  \changes{v6.00}{2024-04-10}{copied over the new extended internal command from xr-hyper. 
+%  It prepends the directory name.}
+% Olivier Michel pointed out that
+% if the aux file was not on texinputs you could not always go
+% \cs{externaldocument}{/some/path/to/file}
+% specifically that worked if file.aux was a `simple'  document with
+% one aux file, but if \cs{include} had been used, the `sub' aux files
+% would not be found by xr in the remote directory.
+% This version calls \cs{filename@parse} to get the directory name of the
+% remote directory, which is then explicitly prepended to the names of
+% any included aux files. 
+%  \changes{v5.06}{2020-05-10}{Remove leading and trailing spaces from
 %    the filename (gh/2223)}
 %    \begin{macrocode}
-\def\XR@[#1]#2{{%
+\def\XR@@#1#2#3[#4]{{%
   \makeatletter
   \def\XR@prefix{#1}%
-  \set@curr@file{#2}%
-  \expandafter\XR@next\@curr@file.aux\relax\\}}
+   \def\XR@nocite{#2}%
+   \ifx\XR@nocite\XR@@nocite
+     \let\XR@bibcite\vadjust
+   \else
+     \let\XR@bibcite\bibcite
+   \fi
+  \def\XR@URL{#4}%
+  \set@curr@file{#3}% 
+  \filename@parse\@curr@file 
+  \XR@next\@curr@file.aux\relax\\}}
 %    \end{macrocode}
 %
 % Process the next |aux| file in the list and remove it from the head of
@@ -161,23 +319,40 @@
 %    \end{macrocode}
 %
 % Look at the first token of the line.
-% If it is |\newlabel|, do the |\newlabel|. If it is |\@input|, add the
-% filename to the list of files to process. Otherwise ignore.
+% If it is |\newlabel|, define \cs{r@}\meta{label}, ensure that it has
+% five label data argument and add the url as the last one.  
+% If it is |\@input|, add the
+% filename to the list of files to process. 
+% If it is |\bibcite|, call a |\bibcite|. 
+% If it is |\new@label@record| add the url and then call it.
+% Otherwise ignore.
 % Go around the loop if not at end of file. Finally process the next
 % file in the list.
 %
 % 2018 update: make sure the arguments are handled outside the |\ifx| test,
+% \changes{v6.00}{2024-04-10}{copied over extended definition from xr-hyper}
 %    \begin{macrocode}
 \long\def\XR@test#1#2#3#4\XR@{%
-  \let\XR@tempa\@gobbletwo
+  \let\XR@tempa\@gobblefour
   \ifx#1\newlabel
-    \let\XR@tempa\@firstoftwo
-  \else\ifx#1\bibcite
-    \let\XR@tempa\@firstoftwo
+    \let\XR@tempa\@firstoffour
+  \else\ifx#1\XR@bibcite
+    \let\XR@tempa\@secondoffour
   \else\ifx#1\@input
-     \let\XR@tempa\@secondoftwo
-  \fi\fi\fi
-   \XR@tempa{#1{\XR@prefix#2}{#3}}{\edef\XR@list{\XR@list#2\relax}}%
+     \let\XR@tempa\@thirdoffour
+  \else\ifx#1\new@label@record
+     \let\XR@tempa\@fourthoffour    
+  \fi\fi\fi\fi
+   \XR@tempa
+    {%
+     \expandafter\protected@xdef\csname r@\XR@prefix#2\endcsname{\XR@addURL{#3}}%     
+    }%
+    {\expandafter\bibcite\expandafter{\XR@prefix#2}{#3}}%
+    {\edef\XR@list{\XR@list\filename@area#2\relax}}%
+    {%
+      \edef\next{\noexpand\new@label@record{\XR@prefix#2}{\unexpanded{#3}{xr-url}{\XR@URL}}}%
+      \next
+    }
   \ifeof\@inputcheck\expandafter\XR@aux
   \else\expandafter\XR@read\fi}
 %    \end{macrocode}
diff --git a/macros/latex/required/tools/xr.pdf b/macros/latex/required/tools/xr.pdf
index 205135ba68..a2ba599a8a 100644
--- a/macros/latex/required/tools/xr.pdf
+++ b/macros/latex/required/tools/xr.pdf
diff --git a/macros/latex/required/tools/xspace.dtx b/macros/latex/required/tools/xspace.dtx
index 807fc9c5df..be20fc9e52 100644
--- a/macros/latex/required/tools/xspace.dtx
+++ b/macros/latex/required/tools/xspace.dtx
@@ -1,6 +1,6 @@
 % \iffalse meta-comment
 %
-% Copyright (C) 1993-2023
+% Copyright (C) 1993-2024
 %
 % The LaTeX Project and any individual authors listed elsewhere
 % in this file.
diff --git a/macros/latex/required/tools/xspace.pdf b/macros/latex/required/tools/xspace.pdf
index 0249feb81e..355a222dc1 100644
--- a/macros/latex/required/tools/xspace.pdf
+++ b/macros/latex/required/tools/xspace.pdf