Domoticz is a Home Automation system design to control various devices and receive input from various sensors.
For example this system can be used with: 

* Light switches
* Door sensors
* Doorbells
* Security devices
* Weather sensors like: UV/Rain/Wind Meters
* Temperature Sensors
* Pulse Meters
* Voltage / AD Meters
* And more ...


The MQTT broker mosquitto is integrated into the package. It requires its own domain or subdomain. It's an optional setting: during install if you set the same domaine as your main app domain, it won't be installed.
You may also install the mosquitto package without using the one provided by domoticz_ynh.