• List / Get (Identity v3: Region list / get #584)
• Create (Identity v3 region create #586)
• Delete (Identity v3 region delete #587)
• Update (Identity v3 Region update #594)

API:
https://developer.openstack.org/api-ref/identity/v3/#regions

Schema:
https://github.com/openstack/keystone/blob/2764b49bc209245276da31693ef31f1525cf17d8/keystone/catalog/backends/sql.py#L34
https://github.com/openstack/keystone/blob/2764b49bc209245276da31693ef31f1525cf17d8/keystone/catalog/schema.py#L22

List:
https://github.com/openstack/keystone/blob/2764b49bc209245276da31693ef31f1525cf17d8/keystone/catalog/controllers.py#L70

Get:
https://github.com/openstack/keystone/blob/2764b49bc209245276da31693ef31f1525cf17d8/keystone/catalog/controllers.py#L78

Create:
https://github.com/openstack/keystone/blob/2764b49bc209245276da31693ef31f1525cf17d8/keystone/catalog/controllers.py#L54

Update:
https://github.com/openstack/keystone/blob/2764b49bc209245276da31693ef31f1525cf17d8/keystone/catalog/controllers.py#L83

Delete:
https://github.com/openstack/keystone/blob/2764b49bc209245276da31693ef31f1525cf17d8/keystone/catalog/controllers.py#L92