The other repositories are partial (they do not contain all packages) and can host updates (packages with newer version) that APT might install.
The following sections will explain the purpose and the rules governing each of those repositories.
That is exactly how Debian approaches it, since adding it in APT's There are numerous non-official sources of Debian packages set up by advanced users who have recompiled some software (Ubuntu made this popular with their Personal Package Archive service), by programmers who make their creation available to all, and even by Debian developers who offer pre-versions of their package online.
will list the different repositories (or “sources”) that publish Debian packages.A package can also be sent there after undergoing subsequent changes which can generate problems.The maintainer then tries to uncover them with help from advanced users who can handle important issues.This archive, which is not officially part of Debian, is a service for users who could need some of those programs — however Debian always recommends giving priority to free software.
The existence of this section represents a considerable problem for Richard M.
After discovering an old server that was still running Ubuntu 11.10 I found that apt-get was no longer working as support for this version ended 9 months after it was released, quite some time ago!