https://login.testing.prozesshub.eu
Central Google sign-in broker. Send your users here:
https://login.testing.prozesshub.eu/authorize?redirect_uri=<your-url>&scope=<google scopes>
They are returned to redirect_uri with a signed
token (RS256 JWT) containing their identity and Google
tokens. Verify it against
/.well-known/jwks.json.