Not quite. Let me explain: info-beamer (the process on each Raspberry Pi) always opens up a local UDP/TCP listen socket on port 4444. This allows other local processes to send data to the running info-beamer process. This can be useful as info-beamer (again, the process) itself cannot, for example, contact any outside service on its own. So it needs to be fed additional non-static data in some way. Using UDP/TCP for that is one way to do that.
Now there are various ways you can do that: If you open the info-beamer port to other machines on the network (here for how to do that, but doing so it usually not recommended as there’s no authentication in any way), another program on another machine can send data. That’s what my netcat call in my previous post did. Another way is to use the device command API call, which essentially allows you to send such UDP packets from anywhere using the API.
The final method is to have a local package service running on each Pi. This isn’t something magic: It’s just that any file named service within a package will be marked executable and will be executed on the Pi when installing that package. Such a package service can be written Python, like this one in the repository you linked. Such a service can also send UDP packets locally to the info-beamer process by sending data to 127.0.0.1:4444.