OIDC specification has "claims" parameter in authorizationEndpoint described in section 5.5 http://openid.net/specs/openid-connect-core-1_0.html#ClaimsParameter .
Strangely enough, the "claims" parameter is described just here, but it's not mentioned in AuthorizationEndpoint parameters : http://openid.net/specs/openid-connect-core-1_0.html#AuthRequest . Also even if parameter is just OPTIONAL, the OIDC conformance testsuite has test for it, which currently fail with WARNING. See attachement for details.
So to remove WARNING, it looks that we will need at least some limited support of this parameter.