Seems like usually queries with shorten return only ids. However, host.get with selectParentTemplates on shorten doesn't return any templates.

Request={"jsonrpc":"2.0","method":"host.get","params":{"output":"extend","selectInterfaces":"extend","selectParentTemplates":"shorten","filter":{"host":"Testhost"}},"auth":"874b9b062dfc1d53c9896103dbda1490","id":23}

Response={"jsonrpc":"2.0","result":[{"parentTemplates":[],"interfaces":{"386":

{"interfaceid":"386","hostid":"10319","main":"1","type":"1","useip":"1","ip":"10.1.2.59","dns":"Testhost","port":"10050"}

,"387":{"interfaceid":"387","hostid":"10319","main":"1","type":"4","useip":"1","ip":"10.1.2.59","dns":"Testhost","port":"4500"}},"maintenances":[],"hostid":"10319","proxy_hostid":"0","host":"Testhost","status":"0","disable_until":"0","error":"","available":"0","errors_from":"0","lastaccess":"0","ipmi_authtype":"0","ipmi_privilege":"2","ipmi_username":"","ipmi_password":"","ipmi_disable_until":"0","ipmi_available":"0","snmp_disable_until":"0","snmp_available":"0","maintenanceid":"0","maintenance_status":"0","maintenance_type":"0","maintenance_from":"0","ipmi_errors_from":"0","snmp_errors_from":"0","ipmi_error":"","snmp_error":"","jmx_disable_until":"0","jmx_available":"0","jmx_errors_from":"0","jmx_error":"","name":"Testhost"}],"id":23}