About SSIDs on FortiWiFi units
FortiWiFi units have a default SSID (wireless interface) named wlan. You can modify or delete this SSID as needed. As with external APs, the built-in wireless AP can be configured to carry any SSID.
The AP settings for the built-in wireless access point are located at WiFi Controller > Local WiFi Radio. The available operational settings are the same as those for external access points which are configured at WiFi Controller > Managed FortiAPs.