get https://{hostname}/edge-diagnostics/v1/gtm/gtm-properties
Lists GTM properties you have access to. You can use the returned hostname values to run Test network connectivity with MTR and Get domain details with dig operations for a GTM hostname. Note, that the Test network connectivity with MTR operation requires also hostname's test and target IP values, that you can get with the List test and target IPs for a GTM hostname operation.