Hope it works well for you rbistolfi
If anyone else wants to test these language packs that would be great. I can't speak/read any language other than english. So it would be nice to get some input good or bad.
If you want to test a language you happen to know, but don't want to mess with your VL configuration. Just install the language pack.
Open up a console, temporarily change the language for that session:
(if you happen to understand Russian) then just type firefox and it will open in your new language. It's very easy.
You will see this warning in your console
Gtk-WARNING **: Locale not supported by C library.
Using the fallback 'C' locale.
But it doesn't seem to have any ill effects.
Each language pack installs a file to /usr/lib/firefox-126.96.36.199/defaults/pref/vl-langpack.js
This file is a firefox preference that will load language packs (on firefox startup) according to what your VL language settings are. It is fine to have as many language packs installed as you wish. But the removal of just one language packs will remove that preferences file and revert your firefox back to the US version. You can reinstall any of the language packs that you wish to keep to replace that file, or you can run this command to replace it.
cat > /usr/lib/firefox-188.8.131.52/defaults/pref/vl-langpack.js << EOF
// This forces Firefox language to switch to locale of machine
// if available.
I'm also thinking about building language packs for Sunbird and Thunderbird. But would like to see if "Mozilla language packs" are useful to VL users before I clutter up our repos with a hundred or so new packages.