Thank you to all (some off-list) that replied with suggestions for
locally marking or moving messages. That encouraged me to take a deep
dive into Mutt's configuration syntax, which for others seeking the
same looks something like this:
subscribe misc@opensmtpd.org
index-format-hook listsub "~C misc@opensmtpd.org" "[OpenSMTPD] "
set index_format="%4C %Z %{%b %d} %-15.15F (%?l?%4l&%4c?) %@listsub@%s"
Changing the Subject header breaks the DKIM signature, so to be
compatible with DKIM (which is required by most large mailservers
nowadays) list software must keep the subject line intact.
That issue appears to be what Authenticated Received Chain (ARC)[1] is
designed to address, although imperfectly.
I see that there are (external?) opensmtpd-filter-auth and
opensmtpd-filter-sign modules on GitHub which implement the spec. That
would perhaps eliminate this particular objection, but other objections
may well remain valid of course :-)
[1] https://en.wikipedia.org/wiki/Authenticated_Received_Chain
Regards
--
Mark Lawrence
