/usr/bin/courier-config
/usr/bin/deliverquota.courier
/usr/bin/maildiracl
/usr/bin/maildirkw
/usr/bin/maildirmake.courier
/usr/bin/makedat.courier
/usr/bin/testmxlookup
/usr/sbin/couriertcpd
/usr/sbin/sharedindexinstall
/usr/sbin/sharedindexsplit
You may install this package on Debian with
apt-get
install courier-base