What is this sm-mta?

I have the following options set in /etc/rc.conf

sendmail_enable="NO"
sendmail_msp_queue_enable="NO"

Yet I keep seeing a lot of sendmail activitity in /var/log/maillog:

Nov 25 03:35:41 foo sendmail[90110]: 2AP2ZeZo090110: to=root, delay=00:00:00, xdelay=00:00:00, mailer=relay, pri=37944, relay=[127.0.0.1], dsn=4.0.0, stat=Deferred: Connection refused by [127.0.0.1]
Nov 25 03:35:41 foo sendmail[90110]: 2AK23ccD044156: to=postmaster, delay=5+00:32:03, xdelay=00:00:00, mailer=relay, pri=487250, relay=[127.0.0.1], dsn=4.0.0, stat=Deferred: Connection refused by [127.0.0.1]
Nov 25 03:35:41 foo sendmail[90110]: 2AK23ccD044156: 2AP2ZeZp090110: return to sender: Cannot send message for 5 days

What is all of this?

And also from sm-mta:

Nov 24 16:12:06 foo sm-mta[56897]: STARTTLS=server: file /etc/mail/certs/dh.param unsafe: No such file or directory
Nov 24 18:39:14 foo sm-mta[12546]: starting daemon (8.16.1): SMTP+queueing@00:30:00
Nov 24 18:39:14 foo sm-mta[12546]: STARTTLS=server: file /etc/mail/certs/dh.param unsafe: No such file or directory
Nov 24 20:47:03 foo sm-mta[75966]: starting daemon (8.16.1): SMTP+queueing@00:30:00
Nov 24 20:47:03 foo sm-mta[75966]: STARTTLS=server: file /etc/mail/certs/dh.param unsafe: No such file or directory

sm-mta doesn't seem to be documented anywhere?

 There are no scripts in /etc/rc.d nor /usr/local/rc.d

Still the log is filling up with this in maillog.

Kind regards.