[Federation] Explicit client registration: Clarify setting of authority_hints by OP in registration statement

[Vladimir Dzhuvinov]

At present (draft 25) the explicit client registration text defers to the entity statement definition on how the authority_hints is to be set. In the context of an explicit client registration response it is sufficient to set the authority_hints to the immediate superior entity in the resolved trust chain (to save effort for the RP).

https://openid.net/specs/openid-connect-federation-1_0.html#name-op-constructing-the-respons

(pt 5)

[Giuseppe De Marco]

We have read this issue during the editor’s c all on 13 Jan 2023, and we need more clarification on this issue and how a PR may come to resolve it. Do you have a proposal to share here in this thread @Vladimir Dzhuvinov ?

[Michael Jones]

We talked about this again during the 20-Jan-23 Federation Editors' call. At this point, we’re waiting on a concrete proposal for how to resolve this issue.

[Vladimir Dzhuvinov]

Will submit a PR.

[Vladimir Dzhuvinov]

PR to address the issue: https://bitbucket.org/openid/connect/pull-requests/430