Eclipse uses GitHub as a source of mirrors.
We populate the information from a script that runs over the portal.eclipse.org metadata
The script uses the project metadata as specified in the Developer Portal. The implementation is quite robust; you can specify your project's Git repositories (one per line) in any of the following formats:
- git://egit.eclipse.org/* (EGit project only)
The script (and other uses of this information at eclipse.org) will normalize the value you provide into an appropriate value.