There's also an error in Phabricator in src/infrastructure/env/PhabricatorEnv.php that can be fixed likewise with a similar diff:

This looks to be a dupe of D21743: Fix a PHP 8.1 issue in lint rendering which seems to use a slightly more idiomatic way of fixing this (using phutil_string_cast() on the supposed string first).

I'd propose for simplicity that the focus switch from largefiles to lfs support for Mercurial repositories. lfs has been added to Phabricator for Git already T7789 and it seems that there'd be less work involved to piggyback on that.

@PhoneixS thank you for the fix. It fixed a very annoying problem here with Windows-1252 encoding in a file name!