[Evolution] Mailing list filter, X-BeenThere

[Kenneth Porter <shiva well com>]

The online help says that the mailing list filter looks for a
X-BeenThere header to do its magic. How universal is this header? Is it
appropriate to complain about its absence on lists that lack it?

(I'm trying to debug a filter for the VNC mailing lists and I don't see
that header in messages from that list.)