/usr/share/myspell/dicts/fr_MC.aff is in hunspell-fr-comprehensive 1:5.5-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/myspell/dicts/../../hunspell/fr.aff
/usr/share/myspell/dicts/../../hunspell/fr.aff