public API for getting the zarr v3 name

Author: d-v-b

changes/2874.feature.rst

@@ -13,7 +13,8 @@ fields on the ``ArrayV2Metadata`` and ``ArrayV3Metadata`` classes. Previously, `
 was a NumPy ``dtype`` object, and ``ArrayV3Metadata.data_type`` was an internally-defined ``enum``.
 After this change, both ``ArrayV2Metadata.dtype`` and ``ArrayV3Metadata.data_type`` are instances of
 ``ZDType``. A NumPy data type can be generated from a ``ZDType`` via the ``ZDType.to_native_dtype()``
-method. The internally-defined Zarr V3 ``enum`` class is gone entirely, but the ``ZDType._zarr_v3_name``
-attribute contains the string value previously associated with that ``enum``.
+method. The internally-defined Zarr V3 ``enum`` class is gone entirely, but the ``ZDType.to_json(zarr_format=3)``
+method can be used to generate a dictionary that has a ``name`` field that contains the string value
+previously associated with that ``enum``.
 
 For more on this new feature, see the `documentation </user-guide/data_types.html>`_