The repo command comes with built-in help that can be accessed using
`repo help` once `repo init` has been run.  There is more documentation
on these websites:

* https://source.android.com/source/using-repo.html
* https://source.android.com/source/downloading.html
* https://source.android.com/source/developing.html

 -- Hans-Christoph Steiner <hans@eds.org>, Mon,  6 Jul 2015 23:37:26 -0700