Ned Freed writes:
MIME entities are only supposed to contain MIME headers,
The definition in 2045 contains this sentence:
Any sort of field may be present in the header of an entity,
but only those fields whose names begin with "content-" actually have
any MIME-related meaning.
so this is actually changing and extending what the document currently
allows. Absent a really compelling case for adding this functionality
I don't think now is the time to revisit this decision.
I agree that once a document is in the queue, the threshold for
attempting a change should be high. Higher than e.g. the threshold for
issuing an erratum.
The reason I'm unhappy today is that I just discovered lots of test
cases. (I wasn't an implementer two years ago, I'm afraid.) I don't
want to have to write code and tests for e.g. Subject being present in
both :mime and :subject.
In fact, if your intention as document editor was that only MIME header
fields should be present, I think I'll be quiet now and write some code
to discard all other header fields. That's simple to implement and it's
always possible to write more complicated code if someone complains.
Arnt