In config.yaml:
zigbee.mqtt:
host: localhost
port: 1883
The parameters are the same documented in the constructor for the plugin (https://platypush.readthedocs.io/en/latest/platypush/plugins/zigbee.mqtt.html) and the backend (https://platypush.readthedocs.io/en/latest/platypush/backend/zigbee.mqtt.html)
