% arara: pdflatex
% arara: makeglossaries
% arara: pdflatex
\documentclass{article}
\usepackage[stylemods,style=alttree]{glossaries-extra}

\makeglossaries
\loadglsentries{example-glossaries-long}
\glsaddall

\begin{document}
\glsfindwidesttoplevelname
\printglossaries
\end{document}
