Yup. Been in there since 8.7, I think. Search somewhere for ``detail'' and/or ``plussed'' in conjuction with ``sendmail''. Regardless, the defaults for generating .cf files allow for it. The local_procmail and cyrus mailers do something intelligent with the detail (what they refer to the local part after the `+'), and the local mailer just throws it away (but leaves it in the ``To:'' header, obviously).