The aim of this post is to try and explain the non-distro specific repositories hosted and run by CentOS. Aside from the main Distribution repositories ( OS, Updates, ISO's ) we also run the following repositories for each Release.

1. Addons : Contains packages required in order to build the main Distribution or packages produced by SRPMS built in the main Distribution, but not included in the main Redhat package tree (mysql- server in CentOS-3.x falls into this category). Packages contained in the addons repository should be considered essentially a part of the core distribution, but may not be in the main Redhat Package tree.

2. Extras : Packages built and maintained by the CentOS developers, that add functionality to the core distribution. These packages have undergone some basic testing, should track upstream release versions fairly closely and will never replace any core distribution package.

3. Contrib : Packages contributed by the CentOS Users, which do not overlap with any of the core Distribution packages. These packages have not been tested by the CentOS developers, and may not track upstream version releases very closely.

4. CentOSPlus : Packages contributed by CentOS Developers and the Users. These packages might replace rpm's included in the core Distribution. You should understand the implications of enabling and using packages from this repository.

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We welcome contributions into the Contrib and CentOSPlus repository. Post a message on the CentOS-Devel mailing list with details of packages you would like to contribute, one of the CentOS developers will then pick it up and work with you on the issue.

You might want to make sure that the same package is not already easily available from some other mainstream repository. And, you should be willing to maintain the packages in sync with upstream releases and fix's.