This is the bsdmainutils package from Debian. It's a collection of common BSD
utilities, compiled from different sources, by the Debian folks. It includes
tools such as the classic 'calendar'.

This SlackBuild uses the Debian sources to create a suitable package for
Slackware. Hdate (and it's python bindings) is a build-time dependency, that
is built in this same package, but not installed. Because it's a package for
Slackware, and not Debian, it bears the following differences from the
original Debian package:
- Utilities that conflict with Slackware's util-linux have been removed.
- /etc/cron.daily/bsdmainutils and /etc/default/bsdmainutils have been
  installed in /usr/doc as cron.daily, and bsdmainutils.default, respectively.
  Please verify that these scripts work on your machine before using them in
  production. They were tailored for Debian, not Slackware!
- The postinst and prerm scripts aren't installed, because they're unnecessary
  in the context of Slackware.
- Slight structure alterations to fit with the Slackware filesystem. See the
  SlackBuild for more details.