When the transmitter receives a GET_PARAMETER request, it MUST verify that the request includes the "Content-Type: application/vnd.ms-wmdrm-extended-operation-request" header. The presence of this header indicates that the entity-body of the GET_PARAMETER request contains a revocation list request message.
The only extended operation currently defined is the revocation list request.
The transmitter MUST process the revocation list request, complying with the rules here. Unless there is an error, the transmitter MUST include a revocation list response message in the entity-body of the response to the GET_PARAMETER request.
The response to the GET_PARAMETER request MUST include a "Content-Type: application/vnd.ms-wmdrm-extended-operation-response" header to indicate that the body of the response contains a revocation list response message.