[SURBL-Announce] All three lists set to distribute plain text only

FWIW I've changed all three lists to send out only plain text.

I have no idea if that's standard practice in Mailman, but like most, ahem, experienced Internet users I prefer my mail messages as plaintext. And it was a simple change of the top default content setting, so I assume it's the most common switch used (after ~not filtered).

Specifically Mailman will filter out any attachments that are not multipart/mixed, multipart/alternative, or text/plain, and convert any resulting text/html messages to plain text.

Messages that have not recursively resolvable plain text are rejected back to the sender with an explanation, if I'm reading the Mailman description correctly.

Jeff C.