Comment 2 for bug 1276722

Horizon team is considering splitting into OpenStack related code and non-related code. Roughly speaking, the former is now under openstack_dashboard and the latter is under horizon directory.
Once splited, the latter will be shipped to PyPI. Regarding the former part we will follow a direction of whole Openstack projects.

There is a discussion about how to use Horizon in requirements.txt in -dev ML and the current solution is to use tarball.
http://lists.openstack.org/pipermail/openstack-dev/2014-March/thread.html#29874