[toast0]

It is (or was) common for mailing lists to keep the From header when forwarding mail to a list. The envelope sender is commonly changed to refer to the mailing list for bounce processing, and often a mailing list footer is added, sometimes the subject is adjusted and other administrative headers are added.

Changing the subject or adding a footer will almost always break the DKIM signature, and DMARC won't like it anyway, because the From address and the envelope sender don't have the same domain (alignment). This makes it pretty hard to use DMARC for a public domain.

It's not so bad to use it for a corporate domain, and it helps a bunch if your domain is being used to source phishing; except that people still think you sent it when it comes from [e-mail] which is clearly some ancient web mailer script that was compromised 20 years ago, but still remains online. (I'm totally not bitter!)