§8.23.

ANNOUNCE

The publisher sends the ANNOUNCE control message to advertise that it has tracks available within the announced Track Namespace. The receiver verifies the publisher is authorized to publish tracks under this namespace.

ANNOUNCE Message {
  Type (i) = 0x6,
  Length (16),
  Request ID (i),
  Track Namespace (tuple),
  Number of Parameters (i),
  Parameters (..) ...,
}
Figure 22: MOQT ANNOUNCE Message

This is one section of the MoQT specification, rendered per-section for quick reference and citation. The authoritative text is draft-ietf-moq-transport-13 at the IETF.