Here is a Sieve language snippet for
identifying an ietf-822 list message:
if anyof (address :contains ["From", "Sender", "Return-Path", "To",
"CC", "Bcc"] "ietf-822", header :contains ["List-Post", "List-ID"]
arrgh. if this is sufficient for your purposes, great - but it's not a
good idea in general to recommend using header fields for this purpose.
it will not do the right thing with forwarded or resent messages or
messages sent to multiple lists to which you are subscribed.
you really want to file things based on envelope information, like MAIL
FROM or (with subaddresses) RCPT TO.