---
features:
  - All methods defined in ``APIExtensionDescriptor`` are now class methods.
    This allows consumers to call them without a reference to an actual
    extension object instance.
fixes:
  - The ``get_extended_resources`` method of the ``APIExtensionDescriptor``
    was updated to also include the underlying API definition's
    ``SUB_RESOURCE_ATTRIBUTE_MAP`` in the returned dict. As a result, the
    ``update_attributes_map`` method now also includes the sub-resources if no
    ``extension_attrs_map`` is passed to it.