Veyon is primarily a computer lab tool to monitor/control a number of computers (Windows/linux). Think multiple VNC viewers in one app.
Here is an overview from Veyon (formerly iTALc):
With Veyon you always have full control over your classroom. You can see all computer screens in an icon view and access individual computers with just one click. Taking screenshots of computers is a one-click operation as well. Draw attention to your lesson by locking all computers and blocking input devices with the help of just one button.
I use it to monitor/control, messaging and troubleshoot kids Windows laptops and would love to be able to have it integrated into HA to monitor and handle automating controls of computers.