This relates to #296 in the sense that I was trying to select fields and thought it was impossible — I hadn't thought to try ^J/^K (which work). suspect this is a good first patch for someone (me?)
Thanks. I have failed to try this as sourcehut's mailbox download has format=flowed which broke git-am and the raw download is un-decoded quoted-printable which breaks patch(1), then I ran out of time. But I look forward to shaving those yaks and getting to give this a try.