Edit presenсe packet

I wanted to change some in presence. When a new user connects, he receives data about already connected users.

<audiomuted xmlns="http://jitsi.org/jitmeet/audio">false</audiomuted><videoType xmlns="http://jitsi.org/jitmeet/video">camera</videoType><videomuted xmlns="http://jitsi.org/jitmeet/video">false</videomuted>

The xml part of the accepted clients. How can I add my own similar field, for example, I want the newly connected users to see the raised hand.