The lxc userspace tool source code is maintained on http://sourceforge.net/projects/lxc and managed with git at http://lxc.git.sourceforge.net
The git clone related command:
git-clone git://lxc.git.sourceforge.net/gitroot/lxc/lxc
When you find you need help, you can check out one of the two lxc mailing list archives and register if interested:
https://lists.sourceforge.net/lists/listinfo/lxc-devel
https://lists.sourceforge.net/lists/listinfo/lxc-users
We also have a bug tracker.