So we know that the OAuth2 scope for the Stadia API is https://www.googleapis.com/auth/stadia.profile found in use by Bungie, but the API documentation isn't posted anywhere yet. Any way we can get a quick list of the endpoints? Or at least can you confirm the base endpoint? My guess is https://www.googleapis.com/stadia/v1 but it very well could be stream or something of the sort.
Any update on this?
That's a very specific question. I would recommend to contact directly the developers either on https://developers.google.com or on https://stadia.dev as there you get a better chance of an answer to your API question.
There is no documentation about this anywhere on the developer page. The stadia.dev site is only used for game publishers to request publishing and managing permissions from Google, not necessarily directly related to Stadia oAuth. Some endpoints specially basic authentication (id/username) would be much appreciated by the community. The oAuth token stated on the original question is correct though.