Under the gateway module, you will find an overview of all gateways associated with the project.
The gateway list also shows which network the different gateways use to communicate. Gateways can be from LoRaWAN, CoAP or even MQTT Client network. With that info you can quickly identify which network this gateway is working on.
Gateways are added to the list automatically, you can not manually add gateways to this list.
Nothing happens if you delete the gateway in this list. It will appear again immediately if any device sends information through this gateway.
Extenders are, for example, wM-Bus repeaters that are used to extend the range of the signal.