mod_http_oauth2: Advertise the currently supported id_token signing algorithm This field is REQUIRED. The algorithm RS256 MUST be included, but isn't because we don't implement it, as that would require implementing a pile of additional cryptography and JWT stuff. Instead the id_token is signed using the client secret, which allows verification by the client, since it's a shared secret per OpenID Connect Core 1.0 § 10.1 under Symmetric Signatures. OpenID Connect Discovery 1.0 has a lot of REQUIRED and MUST clauses that are not supported here, but that's okay because this is served from the RFC 8414 OAuth 2.0 Authorization Server Metadata .well-known endpoint!

module:hook("message/host", function (event)
	local stanza = event.stanza;
	if #stanza.tags == 1 and stanza.tags[1].attr.xmlns == "http://jabber.org/protocol/chatstates" then
		return true;
	end
end, -10);