"Content Type" clarification

We have a debate where someone is interpreting “Content Type” as a free-form _expression_.

Appendix C of the spec notes under payload format and content type:

“Allow the payload format (binary, text) and a MIME style content type to be specified when a message is published. These are forwarded on to the receiver of the message.”

I assume people in the TC had HTTP-style Content-Type expressions in mind with https://datatracker.ietf.org/doc/html/rfc2046 syntax.

Was it discussed and dismissed to make an explicit reference?

mqtt message