I *think* the issue is that I needed to update ~/.muttrc for the change
in gnupg; in particular:
set pgp_decrypt_command="gpg --keyserver pgp.mit.edu --passphrase-fd 0
--no-verbose --batch -o - %f"
was changed to
set pgp_decrypt_command="gpg2 %?p?--passphrase-fd 0 --pinentry-mode=loopback?
--n
I have been using mail/mutt & security/gnupg (latter switched to
security/gnupg20 back when gnupg20 port was created because of a
similar-looking issue to what's described in the first part of the
below narrative) for several years -- without enabling "gpgme" (in
case that turns out to be relevant)