/usr/share/myspell/dicts/fr_LU.aff is in myspell-fr-gut 1:1.0-30.
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