gloss-malayam.ldf has a stray U+FEFF before the \ProvidesFiles:
And so it errors when used with xelatex (lualatex igores the stray input) with "missing begin document":
\documentclass{article}
\usepackage{polyglossia}
\setdefaultlanguage{malayalam}
\begin{document}
test
\end{document}
! LaTeX Error: Missing \begin{document}.
See the LaTeX manual or LaTeX Companion for explanation.
Type H <return> for immediate help.
...
l.3
\ProvidesFile{gloss-malayalam.ldf}[polyglossia: module for Malayalam]
gloss-malayam.ldf has a stray U+FEFF before the
\ProvidesFiles
:And so it errors when used with xelatex (lualatex igores the stray input) with "missing begin document":