Since some months, the license text selector language fallback is broken at Commons:
It apparently worked before (but I am not sure):
(message deleted because it was redundant to the English version)
How to reproduce:
Go to https://commons.wikimedia.org/wiki/Special:Upload?uselang=de-at
and the Lizenz:-<select> only contains one entry. This is because [[MediaWiki:Licenses/de-at]] does not exist. I would, however, expect that in this case [[MediaWiki:Licenses/de]] is used.
See Also: T3495: Improve message source fallback flow