This is a "source" charm, which is intended to be strictly the top layer of a built charm. This structure declares that any included layer assets are not intended to be consumed as a layer from a functional or design standpoint.
Building, pushing and publishing to the charm store is automated by CI to ensure consistent flow. Manually building is useful for development and testing, however.
tox -e pep8
tox -e py34 # or py27 or py35
tox -e build
Freenode IRC: #openstack-charms