Hello,
In particular, we don't include the original From: @domain because of goal #2 [in dmarc.py]. We use --- to imply that something is missing. Perhaps ellipsis would have been a better choice, but we didn't want anything that even hinted at a domain.
OK, that makes some sense. Here's goal #2:
# 2) the original From: address should not be in a comment ordisplay # name in the new From: because it is claimed that multiple domains # in any fields in From: are indicative of spamminess. This means # it should be in Reply-To: or Cc:.
I don't recall there being documentation of this claim. I certainly believe it happens at least occasionally (I know several mail admins who will implement any filter that might eliminate 1 or more spams in the next decade ;-). But is it really a major problem?
I'm coming around to the idea of a general format language for configuring various Mailman-generated texts with a bunch of standard codes (like strftime). There are too many "minority" problems like the OP's (and I suspect "multiple addresses are spam" for that matter) for me to be comfortable ignoring the set, but on the other hand the number of options we'd have to provide to satisfy 1/10th of them would be insane, and unpopular with 99% of the folks considering changing the default.
“It is claimed that multiple domains in any fields in From: are indicative for spamminess” is a rumour, which does not account for real-world feasible use cases.
Since other MLMs have the option to include the full original-From: address in the display-part of the From: header, mailman shall have this option, too.
Greetings Дилян