Binary and Source Packages
Most users of a Debian-based distribution such as Ubuntu will never have to deal with the actual source code that is used to create all of the applications on their computers. Instead, the source code is compiled into binary packages from the source package that contains both the source code itself and the rules for making the binary package. Packagers upload the source packages with their changes to the build systems that then compile the binary packages for each architecture. A separate system distributes the generated binary .deb files and source changes to the repository mirrors.