Perhaps his IMAP server acts as a Usenet gateway -- I've heard of such
setups. But IIRC the mailing list support in Mutt assumes mail from
those lists follow certain conventions -- which header field contains
the list's address and which contains the actual sender's address and
so on. The chances may be slim that his Usenet gateway does this right.
 It's surely in the Mutt documentation. I haven't been on any
real mailing lists for many years so I have forgotten the details.
// Jorgen Grahn <grahn@ Oo o. . .
\X/ snipabacken.se> O o .