Both enwiki and frwiki (at least) use {{FULLPAGENAME}} in [[MediaWiki:newarticletext]], which is unusable, because it is replaced by “API” in VisualEditor.
So the warnings contain texts like
— “You can also start your new article at Special:Mypage/API.” (https://en.wikipedia.org/wiki/Nawak?veaction=edit)
— “Comment faire pour créer l'article API ?” (https://fr.wikipedia.org/wiki/Nawak?veaction=edit)
Version: unspecified
Severity: minor
See Also:
https://bugzilla.wikimedia.org/show_bug.cgi?id=59608