Arvados

#15397 says:

We should remove some unused fields from "api_client_authorization" response: default_owner_uuid, api_client_id, user_id (the _id fields may need to remain internally but should not be published by the API because they are not usable with any other API calls).

This deprecation is currently not announced in the API documentation. If we want to deprecate these fields on the same schedule as all the other API resources, that needs to be done for 2.7.0.