Debian has access to online repositories that contain over 51,000 packages. Debian officially contains only free software, but non-free software can be downloaded and installed from the Debian repositories.

What is in a Debian package?

A Debian “package”, or a Debian archive file, contains the executable files, libraries, and documentation associated with a particular suite of program or set of related programs. Normally, a Debian archive file has a filename that ends in . deb .

Where are packages installed Debian?

Debian already comes with pre-approved sources to get packages from and this is how it installs all the base packages you see on your system (if a user did a net-install). On a Debian system, this sources file is the “/etc/apt/sources.