On Tue, Aug 30, 2022 at 04:07:18PM -0400, Jeff King wrote:

All that said, I don't care _too_ strongly about it. I do suspect the
feature might be better placed in send-email (or possibly in addition).
If you are using send-email, then I think you're not supposed to use
"--from" with format-patch at all, and you have no way of accessing this
feature.

This "not supposed to" came from me looking at the documentation. But
this discussion implies that it's maybe not that big a deal:

  https://lore.kernel.org/git/xmqq8twlqwan.fsf@gitster.mtv.corp.google.com/ (local)

Apparently we were considering enabling "--from" by default, but I don't
think that ever happened.

-Peff