Provider Reference File Schema missing provider_group_id?

[jimiyash]

On the in-network rates page https://github.com/CMSgov/price-transparency-guide/tree/master/schemas/in-network-rates#provider-reference-object it references a provider_group_id. However, on the provider_reference page and schema, there is no field for provider_group_id https://github.com/CMSgov/price-transparency-guide/blob/master/schemas/provider-reference/README.md).

Is this by design or is it missing?

[tdfow]

Provider Reference Object has the provider_group_id, where either a provider groups or location attribution will be required in the provider reference object.