Zelda? Not a Microsoft franchise, as I'm sure you know. Not that that stops the official Xbox Facebook account from telling you all about it...and also James Franco. For some reason!
This sort of thing isn't quite an isolated incident — before, the Xbox UK account has posted about The Last of Us. That's also not a Microsoft franchise, as I'm sure you're aware.
EDIT: Then there was this, as pointed out by reader waffle ryebread.
If you're snarky, you might wonder if the people in charge of these accounts know what franchises are on what platforms. If you're not snarky, you might just think, hey, why not spread the love when it comes to great game franchises? Nothin' wrong here, even if it comes off as slightly weird.