after a user reported a discrepancy between two versions of the autonym for the Czech language used in different contexts in MediaWiki, I noticed it comes from a difference between the MediaWiki core Names.php and CLDR data (via the CLDR extension’s CldrNames). Originally, I just intended to submit a patch to Names.php unifying those two to the CLDR version, but then I thought the problem might exist in other languages, too.
So, I compiled a list  of 39 differences in language names between MW core and the CLDR extension. Some of those differences are just case changes, some of them might be errors in one of the sources, some of them just random choices between two equally valid versions (like in the Czech case, it’s not like one of them is generally better than the other, it’s just that consistency would be better).
I definitely do not intend to change all those languages I do not understand, but maybe other people could be interested in checking their language in the list…
-- [[cs:User:Mormegil | Petr Kadlec]]