Signal for when an engine gets added

Hi there. Working on a control device driver for SooperLooper, I start pinging SL’s OSC server, and then stop after a while. But I’d also like for it to be robust, so re-initialising stuff if the SooperLooper engine gets removed and re-added, and not consuming resources when there is no SL engine running.

So here’s my question: is there some signal or method a ctrldev driver can hook into whenever an engine gets added or removed? I couldn’t find it perusing the code base, but I may be looking at the wrong places.