[msmtp-users] Matching an account with a "plussed" address

[Stephane Bortzmeyer <bortzmeyer@...50...>]

I'm currently using msmtp from mutt and I choose the account based on
the "from" (mutt is configured with envelope_from=yes).

It works with "ordinary" addresses like "stephane@...51...". But
I'm an user of "plussed" addresses like
"stephane+amazon@...51..." because it allows me to have many
identities without the trouble of configuring them.

mutt is fine with them (in alternates, for instance, you can set
addresses with stephane\+[^@]+ and therefore all plussed addresses are
accepted) but not msmtp.

How to match a plussed address?