Detect a monitor getting connected/new display configuration

I want to detect when a new monitor is connected to my laptop. Is there any event that I can listen to? There must be something because when I connect a monitor, XFCE prompts me with the Display settings application to configure the monitor.

I would also like to detect when the display configuration changes (e.g. after I configure the display from the Display settings application). I want to restart a process (conky) whenever the display configuration changes.

I’ve tried looking for this with no success. Maybe I don’t know the right keywords to search for? Any guidance would be greatly appreciated.