We have got a big screen in our office connected to an old PC, whose only purpose is to display information generated by software such as Munin, Nagios, etc. It is running Debian with Xfce to be able to run on that machine. Still it is a XServer!
What I would like to do, is to connect any machine (Linux, macOS, but maybe also Windows) remotely to that XServer and mirror the clients screen (so not
ssh -X!!!). So anyone can share a view on his screen with the others in the room.