mailbox.mbox Status/X-Status flags RFC?

[Tim Chase]

Playing around with mailbox.mbox, I noticed the flag get split
across Status/X-Status headers.  I dug into the source and read at
[1] to see the *how* but I'm curious as to the *why*.

When I pulled up RFC-4155[2] (mbox), it didn't seem to mention
anything about the Status/X-Status stuff, and the MaildirMessage
stores flags differently (and with different meanings).

Anybody have some insight (or an RFC document) that would help this
make sense to me?

Thanks,

-tkc


[1]
http://docs.python.org/library/mailbox.html#mboxmessage

[2]
http://tools.ietf.org/html/rfc4155