Browsing through the Beta Features tab on my en-wiki Preferences page, I note that under supported skins for VE are "<skinname-apex>" and "<skinname-minerva>".
Topic on VisualEditor/Feedback
And that doesn't show up properly here - basically the problem is instead of listing the skin names in plaintext you get some barbled code.
That's very odd. Not quite sure why that's happening; will try to find out. Sorry for the disruption. (Note that that only shows if you're not using any of those four skins, so only affects a few dozen editors.)