[Mailman-Developers] Thinking about list footers

Right now list footers are a common feature of Mailman and other MLMs. The typical way of doing this is to just append some content, probably after "--", that indicates the location of archives and maybe some administrative information (unsubscribe instructions, for example).

What's the expertise on the idea of adding footers in a new MIME text/plain part rather than just bolting it onto the text as-is? (Or is that already done?) What do MUAs generally do with multipart text/plain bodies?

And along those lines, do any MUAs do useful things with the various List-* fields, other than permitting one to sort on them?

I'm brainstorming on some possible solutions to DMARC and DKIM matters, and I don't want to reinvent any wheels.

Thanks, -MSK