Fontmatrix is a free and open source font management application for Linux, macOS, and Windows. It is released under GNU General Public License v2.0.It helps you to manage all your system fonts collection and enable and disable availability of fonts and font families easily using this app. It shows all font chart and font info, you can extract fonts, view truetype tables, comparing fonts glyph by glyph and comes with font playground support. You can also import and export fonts easily.
Install Fontmatrix on Ubuntu Linux
Fontmatrix is available via flatpak package from flathub for Linux. You can install it via the terminal application. First install flatpak and flathub on your system and restart your system. After that open terminal app (ctrl+alt+t) and run below Fontmatrix flatpak installation command.
flatpak install flathub com.github.fontmatrix.Fontmatrix
After that you can run Fontmatrix app using below command.
flatpak run com.github.fontmatrix.Fontmatrix
And uninstall it via
sudo flatpak uninstall com.github.fontmatrix.Fontmatrix