Package: nullmailer

"nullmailer" package binaries on Debian:

/usr/bin/mailq /usr/bin/newaliases /usr/bin/nullmailer-inject /usr/bin/nullmailer-smtpd /usr/sbin/nullmailer-queue /usr/sbin/nullmailer-send /usr/sbin/sendmail

You may install this package on Debian with apt-get install nullmailer