We already removed the footer because it was incompatible with DKIM signing. Keeping the "[Bitcoin-dev] " prepend tag in subject is compatible with DKIM header signing only if the poster manually prepends it in their subject header.

I still see footers being added to this list by SourceForge?

Opinions?

I've asked Jeff to not use his @bitpay.com account for now.

The only real fix is to use a mailing list operator that is designed to operate correctly with DKIM/DMARC, either by not modifying messages in transit, or by re-sending (and ideally re-signing) under their own identity.

Though I'm sure this won't be an issue for the Linux Foundation, the latter approach is dangerous because it means the list operator takes full responsibility for any spamming that occurs from that domain. If the mail server is ever hacked or spammers start posting to the lists themselves, all that spam will be seen as originating from the listserv itself and the reputation will be degraded. It can end with everyone's mail going to the spam folder.