But where are those settings? I installed language pack for Fedora Template, restarted and its language didn’t change. Then I looked its settings and found no settings related to language. There was parameter “Allow UTF-8 window titles” but changing it to “Allow” didn’t help. Also looked in “Qubes Global Settings” and in “Qubes Template Manager” - there are no settings related to language.
Also tried to install language packs for Debian Templates (my defaults) and Whonixes and each time it was saying that it can’t locate language pack. For test tried to install exactly that German pack you said and it can’t locate it too. Probably it means the language pack names were changed. How to find out what new names are?