I can’t remember off the top of my head, but I think they are using the database of either IGDB or GiantBomb. You can add your game on both if unsure.
It’s worth mentioning it takes some time for Twitch database to refresh, so I’d wait a bit after submitting a new game.
It'll be IGDB then. One of our games has a Twitch listing (Bunny Hill Horror) and this appears on IGDB but not Giant Bomb so- through my amazing powers of deduction- I'd go with that...
