BusyBox combines tiny versions of many common UNIX utilities into a single small executable. It provides minimalist replacements for the most common utilities you would usually find on your desktop system (i.e., ls, cp, mv, mount, tar, etc.). The utilities in BusyBox generally have fewer options than their full-featured GNU cousins; however, the options that are included provide the expected functionality and behave very much like their GNU counterparts.
This package installs the BusyBox binary but does not install symlinks for any of the supported utilities. You can use /bin/busybox --install to install BusyBox to the current directory (you do not want to do this in / on your Debian system!).