Neutron extensions
Neutron extensions allow a plugin to extend the Neutron API to provide advanced functionality or to expose a capability before it has been incorporated into an official Neutron API.
Listing Neutron API extensions
To list the extensions available in Neutron, use the Neutron ext-list command as follows:
Syntax: ext-list
The returned output includes the alias and name of the available extensions:

Showing the details of an API extension
To show the details of an API extension, use the Neutron ext-show command as follows:
Syntax: ext-show EXTENSION_ALIAS
The EXTENSION_ALIAS keyword represents alias of the extension provided in the ext-list output. The returned output includes the alias, description, name, namespace, and updated date of the specified extension.
To find more information on creating Neutron API extensions, please visit the Neutron development wiki at https://wiki.openstack.org/wiki/NeutronDevelopment.