A definitive authoritative specification for all variations of the
mbox database format is explicitly not the objective, for several
reasons.
that's fine. I fully support registering application/mbox as a media
type.
For
one thing, such a definition is outside the IETF's purview, the same
as a definition for Outlook or Eudora or other vendor/platform-centric
database formats would be.
I have to disagree here. Perhaps standardizing mbox would be outside
of IETF's purview, but I think it would be valuable for IETF to publish
a peer-reviewed Informational description of (1) existing practice for
mbox files and (2) recommended practice for reading and writing mbox
files. I just don't think that this should be critical path for getting
application/mbox registered.