In the backend system you can find this activity in the Implementation Guide (IMG): In transaction SPRO open the SAP Reference IMG and navigate to .
In this activity you can display the models and the assignment of models to services. Thus you get an overview on the existing models and services.
This is a read-only activity which simply provides an overview on existing configuration settings. The view cluster can still be used to display all registered services and models. The maintenance activities are done via Maintaining Models and Services.