Missing documentation: broker service

[hackerfactor]

The specifications section 4.1 mentions a "broker service". https://c2pa.org/specifications/specifications/1.4/attestations/attestation.html#_trust_brokers_and_rats

1. Is this related to the "known certificate" list? (ref: Missing documentation: known certificate list #50)
2. How does a verifying service identify the list of broker services?
3. The existing documentation (section 4.1) references RFC9334. This RFC describes a high-level process (architecture overview) but not the specific implementation for the query. Assuming the verifying service can identify a broker service, what protocol is used to query the service?

[lrosenthol]

The Broker Service is specific to Attestations - which is an extension to the Trust Model of C2PA. This is described in the Attestation spec at https://c2pa.org/specifications/specifications/1.4/attestations/attestation.html#_c2pa_trust_model_overview