DEB, Debian Software Package (.deb)
The DEB Archive file format
DEB files, or Debian Software Package files, are compressed files most commonly used in the Unix operating system. They are used in different Linux versions, e.g. Ubuntu, Kubuntu or PCLinuxOS. DEB files are used to perform software installation on these operating systems.
Technical details of DEB files
DEB files contain two otherwise compressed archives. These archives have either been compressed using the bzip or gzip compression algorithm. One of the archives is used for the installer's control information, the other one contains the actual compressed data. With Debian 0.93, the DEB file is implemented as an archiver (ar) archive.