This app uses the Aedes nodejs library: https://github.com/moscajs/aedes
This app is a nodejs based MQTT broker. When installed this can be used with the Owntracks client, MQTT client and other apps that use the MQTT protocol to communicate with Homey. When using this app there is no need to use a cloud based MQTT broker or host a broker on a homeserver.
After installing the app, please go to the settings page and enter a port number (usually 1883) where the broker should listen on. Also add users that can have access to the broker.
The MQTT Broker for Homey has a settings page where you can configure the following: