These are just names for openHAB if i remember correctly. No hard connection to zigbee2mqtt. The connection to zigbee2mqtt is done via the items and channels.
But i usually set the friendly name to the device name, in this case SZMS. (SZ defines the room, MS the device type)
Install Mosquitto
a. Run openhabian-config
b. Select Optional Components
c. Select Mosquitto and follow the prompts; choose a username and password if desired
Install zigbee2mqtt
a. Run openhabian-config
b. Select Optional Components
c. Select Zigbee2MQTT and follow the prompts; include the username and password from 1.c. if included. Be sure to select the correct adapter for your zigbee transceiver.
Install the MQTT binding in the OH3 UI
Create a MQTT Broker thing in the OH3 UI and use localhost for the hostname/IP
Add devices to the Zigbee2MQTT system using the UI at [IP address]:8081
a. Give the devices friendly names in the UI
Create a Generic MQTT thing in the OH3 UI; ensure you select the MQTT broker created in step 4
Add channels for the desired channels exposed by the device
i.e.: MQTT State Topic: zigbee2mqtt/[Friendly Name]/action
Now I just need to think of how to best-handle triggering on a button press since the ‘action’ state doesn’t change from “on” between multiple button presses. Unless there’s a better scheme, the only thing I can think to trigger off is a change in the ‘action’ or ‘battery’ or ‘linkquality’ channels since at least one of those should change with each button press…