/var/lib/locales/supported.d/fr is in language-pack-fr-base 1:16.04+20160415.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 | fr_LU.UTF-8 UTF-8
fr_CA.UTF-8 UTF-8
fr_CH.UTF-8 UTF-8
fr_BE.UTF-8 UTF-8
fr_FR.UTF-8 UTF-8
|