An OData API is a standardized REST API, so this means you can also consume it with the REST client functionality in Mendix, e.g., Call REST service activity in a microflow. To simplify this, every OData REST API also provides an OpenAPI contract and a Swagger test page. If you navigate to the source application in a browser on /api-doc/ you'll find the OData contract, the OpenAPI contract and a swagger test page.