Localised language names

Mediawiki in various places is presenting language names in the user's interface in his own language

F.e. <nowiki>{{#language:en|el}}</nowiki> gives me "Αγγλικά" (in greek)

But <nowiki>{{#language:sr-el|el}}</nowiki> gives me "Serbian (Latin script)" (in english)

Where can I translate or modify these language names?