PUBLISH_NAMESPACE — MoQT draft-22 §9.14.

The publisher sends the PUBLISH_NAMESPACE message as the first message on a new bidi stream to advertise that it has tracks available in namespaces matching a Track Namespace Prefix.

PUBLISH_NAMESPACE Message {
  Type (vi64) = 0x6,
  Length (16),
  Request ID (vi64),
  Track Namespace Prefix (..),
  Number of Parameters (vi64),
  Parameters (..) ...
}

Figure 18: MOQT PUBLISH_NAMESPACE Message

Request ID: See Section 6.4.2.1.
Track Namespace Prefix: A Track Namespace as defined in Section 8.7, matched as a prefix (see Section 2.4.2).
Parameters: The parameters are defined in Section 9.20. The only parameter that can appear in a PUBLISH_NAMESPACE is AUTHORIZATION_TOKEN.