On the request or response? I'm thinking for things like https://www.jvt.me/posts/2023/03/08/twilio-who-credentials/ it'd be nice to have an endpoint to go to similar to how https://www.jvt.me/posts/2023/01/09/aws-who-credentials/ works. I know GitHub returns headers to indicate OAuth2 scopes which is quite handy
by 
Jamie Tanna
.