[Mailman-Developers] Patch for HyperArch

[Stephen J. Turnbull]

Mark Sapiro writes:

 > The Received: header check is important. For an "imported" mbox, the
 > From_ separators may reflect when the mbox was exported from it's source
 > rather than the message date. If the messages have Received: headers,
 > the later ones at least tend to have good dates.

Overengineering (seems to be becoming a habit?) perhaps, but if you're
going to parse one Received field, why not do them all, sort, and take
the latest reasonable one?  Leaving the sorted list on msg_data might
also be useful to spam filters (although we don't really want to
recommend spam filtering in Mailman...).