The Courier mail server suite is an integrated mail/groupware server
based on open commodity protocols, such as ESMTP, IMAP, POP3, LDAP,
SSL, and HTTP.  Courier provides ESMTP, IMAP, POP3, webmail, and
mailing list services within a single, consistent, framework.  Individual
components can be enabled or disabled at will and the configuration
of the entire Courier software suite can be managed from a web-based
administration interface.

This is a meta package that pulls in dependencies for the various
Courier mail services.