The Android GitHub account provides a read-only mirror of some of the most common repositories from the Android Open Source Project. You can view the source code and review the history of the project, just like any other repository on GitHub. However, because this is a mirror, some things like contributing to the project work a little differently, which we'll talk about below.
Submitting bugs and patches
Android has specific processes for reporting bugs and submitting patches which developers will need to follow in order to contribute. The Android team does not monitor any issues or pull requests filed against the GitHub mirrors. Additional information can be found in the contributing section of the Android website.
Using the repo tool
When working with the Android source code, developers use the repo tool to checkout the code from the official git repositories. Because of differences in how repositories are named, repo will not work with the Android mirror on GitHub. Several people have published guides on using repo with GitHub, but you're on your own there.
Finally, the freshness of the GitHub mirrors are provided on a "best effort" basis (though they're generally less than an hour behind). Additionally, not all repositories may be mirrored to GitHub. To see the most up-to-date list of Android repositories, visit https://android.googlesource.com/.