I’m curious how many european countries outside the Union will follow. Swiss cooperative Migros stopped labelling their food product, because it cost too much and was barely used.

The SILL About page translated explains the list :

https://code.gouv.fr/sill/readme

Why this catalog?

The socle interministériel de logiciels libres (SILL) is the reference catalog of open-source software recommended by the French government for use throughout the administration.

This catalog helps administrations find their way around the open-source software they are encouraged to use, in line with Article 16 of the French Law for a Digital Republic