Package: courier-authlib-userdb

"courier-authlib-userdb" package binaries on Debian:

/usr/sbin/makeuserdb /usr/sbin/pw2userdb /usr/sbin/userdb /usr/sbin/userdbpw /usr/sbin/userdb-test-cram-md5

You may install this package on Debian with apt-get install courier-authlib-userdb