I am seeing the game pass quests as of last night and was wondering about what the notifications I was getting were all about.
I was playing Slay the Spire and got three notifications for playing a game pass game, getting an achievement in said game and logging in on the mobile app. It is a neat system and I'm glad they added it. You can find the quests under your achievements page on the left side.
I haven't played Slay the Spire in a while and I finally beat the real game for the first time with the Ironclad and got the true ending. I had an amazing run. It is such a great game. Definitely one of my personal GOTY.