Last modified: 2014-11-02 15:02:33 UTC
The blue "More details" button in #mediaviewer/ should use the &uselang= on the local wiki.
Example: Users from dewiki should receive the german interface (&uselang=de) Users from itwiki should receive the italian interface (&uselang=it) etc.
They do: https://de.wikivoyage.org/wiki/Tiflis#mediaviewer/File:Central_part_of_Tbilisi.jpg Not sure why this doesn't work on the Wikipedias, maybe it has to do with the ongoing deployment or the localizations did not sync yet or something. Definitely not an issue with the extension code.
Can't reproduce now on dewiki or itwiki. Any such problem was probably caused by stale caches.