I'll grant you, I can't find it, but I seriously think you all are just jumping to assumptions here. I will eat crow if it turns out otherwise but I've seen people again, and again, and again jump at "There's an xbox logo there, its coming!" And it hasn't. There wa sa press release last year where it mentioned Xbox by mistake.
There's it showing under Gamepass branding several times over the last year (one such example), year and a half, and nothing. And I seriously doubt they'd tease it like this too.
There's been "leaks" about them putting it on game pass for ages, I never give those a second thought.