List Flag: mime-moderation

Causes messages forwarded to list owners to appear to come from listmanager
and look like a MIME-encapsulated message.  The default (and perhaps
incorrect) behaviour is to simply resend the message without otherwise
modifying it, so the submission appears to come from the original submitting
user and looks like a regular piece of e-mail.

Has no effect unless "moderated" is also set.

See also: Moderation moderated