REST API v2 Documentation - registration_data collection fields list

Hi everyone - I am doing some initial learning/scoping on the REST API v2 fields available.  I am looking for user registration date and anything else that might be included in the registration collection.  When I navigate from the users collection field list > registration_data.  I just see a shell page with the error message "the widget could not be displayed" on all sections.  Am I looking in the wrong spot?

Thank you in advance!

Kate