I was exploring the OAuth 2 device flow recently - and came across this url
urn:ietf:wg:oauth:2.0:oob
The service asked me to keep this as the redirect URL if I was using device flow.
I also read this whole paper https://datatracker.ietf.org/doc/html/draft-ietf-oauth-device-flow-06 and there is no mention of such a URL.
I was hoping to find out more information about this and any resources on the internet where its origins were discussed.
EDIT
I found the following - https://www.ietf.org/mail-archive/web/oauth/current/msg09988.html
The person also asks for clarification on why is this URL absent from OAuth 2 spec.
But it does not seem to have a precise response from anyone.