You have come across the VMware-NSX family of Neutron plugins
The homepage for the VMware-NSX project is on Launchpad.
Use this site for asking for help, and filing bugs. Code is available both git.openstack.org and github.
For help on usage and hacking of VMware-NSX, please send a message to the openstack-dev mailing list.
For information on how to contribute to VMware-NSX, please see the contents of the CONTRIBUTING.rst file.