GAS SSO oauth2callback redirect URL
The oauth2callback redirect URL is the URL of the GAS delegation service where the Genero Identity Provider (GIP) or OpenID Connect/OAuth IdP will redirect the user-agent to get the OAuth2 ID token.
The redirect URL (or URLs) is the URL of the OpenIDConnect service on the GAS where the app has been installed. It is the GAS URL + address of the OpenIDConnect service (provided by default in GWS, and called OpenIDConnectServiceProvider.xcf) + the entry point of the service (by default, "oauth2callback") where the IdP will redirect the user-agent to provide the OAuth2 ID token.
Following this explanation, unless some URL rewriting has occurred and is configured in the web
server, the URL will be:
http[s]://host:port/[gas/]ws/r/services/OpenIDConnectServiceProvider/oauth2callback