Jeff King [off-list ref] writes:
You should start the first line of the message body with:
From: Original Author [off-list ref]
git-send-email will do this automatically if the author of the commit you
are sending does not match your identity (you may also need to use "git
commit --author" to make sure the author is set correctly in the
commit).
Thanks.
FYI, the commit in question is 28e29ee3 (format-patch: give an
overview of what a "patch" message is, 2021-03-24) and I think it is
ready for 'next'.