cvsroot is a script to help keep track of multiple sites when using CVS, and in particular the CVSROOT and CVS_RSH environment variables for those sites. It creates a $HOME/.cvsroot file, with shortcut names representing the different CVS sites. The new environment variables appropriate to the site selected will then be set, and a new shell will be spawned to keep the variables. In this way, you do not have to keep setting the environment yourself, and can rely on the script to keep track of things for you.
Debian package information is generally stored in files having a special file format, dubbed the Debian control file format (dctrl), a special case of the record jar file format. These tools operate on any files conforming in a general sense to that format, and are therefore widely applicable whenever this format is in play. The tools in this bundle are grep-dctrl, sort-dctrl, join-dctrl, and tbl-dctrl.
EPOR is an extensible package organiser for Unix-like systems. It's written to trace filesystem changes (something being installed) and save this information in a simple text database (this, as any other provided feature, is customisable via the embedded Guile interpreter). Database entries contain information supplied by the command line (package name, version, etc.) and traced by filesystem changes (new directories, files, etc.). This is achieved using the "LD_PRELOAD method''.
fakechroot provides a fake chroot environment to programs. A fake chroot allows you to run programs which require root privileges on an unprivileged user account. For example, you can create a Debian bootstrap or a development environment and build packages inside a chroot'ed system using a standard non-root user account. You can then use the apt-get command to install other packages without root privileges.