Describe the feature
Based on some documentation there is a way to return refresh token expiration via value in response 'refresh_token_expires_in'.

https://learn.microsoft.com/en-us/linkedin/shared/authentication/authorization-code-flow?context=linkedin%2Fcontext&tabs=HTTPS1#response

I would like to have this information when getting access token (so we know how long refresh token is valid).

Additional context
refresh_token_expires_in is not defined in OAuth2 specs (but specs allowed returning additional properties), but a lot of oauth2 server do support this parameter.

• Does the feature apply to OAuth1, OAuth2 and/or OIDC?
  OAuth2
• Does the feature apply to client or server side code?
  Server side