\input{umtest-preamble}

\usepackage{unicode-math}
\setmathfont[Colour=FF0000]{xits-math.otf}

\begin{document}

\ExplSyntaxOn
[$\l_um_mathstyle_tl$]\ 
[$\mathrm{\l_um_mathstyle_tl}$]\ 
[$\mathup{\l_um_mathstyle_tl}$]\ 
[$\mathit{\l_um_mathstyle_tl}$]

[$\mathbf{\l_um_mathstyle_tl}$]\ 
[$\mathbfit{\l_um_mathstyle_tl}$]\ 
[$\mathbfup{\l_um_mathstyle_tl}$]

[$\mathsf{\l_um_mathstyle_tl}$]\ 
[$\mathsfit{\l_um_mathstyle_tl}$]\ 
[$\mathsfup{\l_um_mathstyle_tl}$]

[$\mathbfsf{\l_um_mathstyle_tl}$]\ 
[$\mathbfsfit{\l_um_mathstyle_tl}$]\ 
[$\mathbfsfup{\l_um_mathstyle_tl}$]

\end{document}
