Following these instructions as well as the comments in there, I was able to get Vidyo, the proprietary videoconferencing system that Mozilla uses internally, to work on Ubuntu 18.04 (Bionic Beaver). The same instructions should work on recent versions of Debian too.

Installing dependencies

First of all, install all of the package dependencies:

sudo apt install libqt4-designer libqt4-opengl libqt4-svg libqtgui4 libqtwebkit4 sni-qt overlay-scrollbar-gtk2 libcanberra-gtk-module

Then, ensure you have a system tray application running. This should be the case for most desktop environments.

Building a custom Vidyo package

Download version 3.6.3 from the CERN Vidyo Portal but don't expect to be able to install it right away.

You need to first hack the package in order to remove obsolete dependencies.

Once that's done, install the resulting package:

sudo dpkg -i vidyodesktop-custom.deb

Packaging fixes and configuration

There are a few more things to fix before it's ready to be used.

First, fix the ownership on the main executable:

sudo chown root:root /usr/bin/VidyoDesktop

Then disable autostart since you don't probably don't want to keep the client running all of the time (and listening on the network) given it hasn't received any updates in a long time and has apparently been abandoned by Vidyo:

sudo rm /etc/xdg/autostart/VidyoDesktop.desktop

Remove any old configs in your home directory that could interfere with this version:

rm -rf ~/.vidyo ~/.config/Vidyo

Finally, launch VidyoDesktop and go into the settings to check "Always use VidyoProxy".