The localizatin de-formal is not an independent localization. Instead, it only contains the messages that differ from plain de. When it not differs, it should fall back to de. Keeping a seperate message in de-formal that does not differ from the correspondent message in de is an unnecessary hassle for future maintenance.
"yourgender": "Welches Geschlecht haben Sie?",
"yourgender": "Form der Anrede",
I don't speak German, but messages don't look identical to me. The first one has the formal "Sie".
I think this is some kind of fallback that took over when Kghbln deleted the page on translatewiki (https://translatewiki.net/wiki/MediaWiki:Yourgender/de-formal). Before he did, the messages were identical. I do not understand how these fallbacks work.
The fallback uses an outdated translation that no longer fits in the context since the three possible answers have been changed. The old version fitted a context where the question was about finding out the user's sex (Welches Geschlecht haben Sie? ‘What sex do you have?’). Possible answers included Ich bin weiblich (‘I am female’) etc. In the current context, the question no longer is about the user's sex, but about the preferred grammatical gender. Possible answers include „Der Benutzer“, „seine Diskussion“, „er bearbeitet“ usw. (‘“The he-user”, “his discussion”, “he edits”, etc.’) etc. This only makes sense when the question is Form der Anrede (‘form of addressing’) – which does not change when using formal Sie.