This directory only host a dummy package, that contains only its
description but is associated to a .dep file listing all packages in
the mate set of packages. This allows an easy maintenance:
- to install all packages from the set run as root:
  slapt-get --install-set mate
- to install and possibly update all packages from the set run as root:
  slapt-get --install-set mate --reinstall
- To upgrade all installed packages including those from the set run as
  root:
  slapt-get --upgrade