RE: MPEG asks for MIME review for the MPEG21 file format 
I believe the +xml suffix should be reserved for media types whose content
can be
parsed without any preprocessing by a generic XML parser. A reply
from David Singer indicated that the proposed MPEG 21file format is "binary
and contains within it either XML text or BiM-encoded XML (like a ZIP
archive
with an XML document as the main document.)"

In that case, the use of +xml would (IMO) be inappropriate.

I thought this was clear form RFC 3023, but perhaps not.

Larry


