Something very weird is going on with Serbian language on Wikidata, so I wanted to draw more attention to it. As always, this is probably applicable to Chinese etc. as well.
It used to be that, if someone visits Wikidata from Serbia, Serbian language did not appear in the list of languages for adding label and description. This is described in https://phabricator.wikimedia.org/T121747
However, as of right now, if someone visits Wikidata from Serbia, he will get Serbian language twice: in Cyrillic (српски) and Latin (srpski) variant. To my knowledge, it has never been discussed to conclusion whether there should be independent labels for the variants. Either way, one of the consequences of this is that all the Serbian labels that have been entered so far are invisible in this list.
It gets even funnier if you go to https://www.wikidata.org/wiki/Q3711?uselang=sr-el since now you get Serbian three times: as "srpski (latinica)", "Serbian (Cyrillic script)" and "српски". It appears that the first is sr-el, the second is sr-ec and the third is the new sr-cyrl.
I didn't want to play with editing, since this is a mess already. It appears that this is caused by an attempt to fix T121747 while simultaneously changing Serbian-language codes (https://phabricator.wikimedia.org/T117845). Either way, I believe it warrants more attention.