relationship of normative statements to the conform target(s), is unclear.

The relationship of normative statements and their subject to the type of implementation expected to conform (the conformance target(s)) is unclear.
For example, we see normative requirements in 2.4 "Operation Addressing".
but we have hard time to relate these to an implementation type that we ultimately want to conform:

"Each message transmission MUST either identify the operation ...." What is a "message transmission"? is that the same as a message? Ultimately does this requirement concern an MDE that issues message? Or another client entity? If not specified in the body of the specification, such connection between the normative req and the entity supposed to conform (a conformance target), should be specified in the conformance clause.

"Each operation MUST be either a REQUIRED operation... " Same here: what kind of implementation has the ultimate responsibility to conform here?

"The response to a request for an operation not supported by the court MUST be reported ..." Same here: what implemenation do we have in mind here, that will need to comply to that requirement in order to conform to the specification? Who is responsible for sending these responses?

It is OK to have normative requirements targeting various objects or exchanges, but there must be a clear association with a conformance target. A conformance clause should do this if not the specification body. Like:

4. Conformance (section)
4.1 Conformance targets:

• sending MDE
• receiving MDE
• ...

4.2 Conformance clause for a "receiving MDE":
An MDE conforming to this specification as a "receiving MDE" is an MDE that :

• implements operations that satisfy requirements in 2.4, ....
• interprets received messages accordig to requirements in 2.5, ...
• generate responses and errors as required in 2.4, 2.6, 2.14, ...

• ...