Install applications from Flatpak
Testing
Flatpak is a tool to package and distribute applications for Linux, independent of the distribution. It's a containerized packaging platform similar to snap. The Flathub repository provides many open-source and proprietary applications that you can install using Flatpak. Flathub is similar to Snapcraft in the snap ecosystem.
Support for Flatpaks on Ubuntu
Ubuntu supports Flatpak on a community basis through the Universe repository since Ubuntu 18.10. Many Ubuntu users install additional applications as Flatpaks alongside deb and snap packages.
The recommended usage of Flatpak on Ubuntu is somewhat different than on other Linux distributions with the GNOME environment. This is because Ubuntu comes with the App Center instead of GNOME Software, which manages Flatpaks on other distributions. To make sure that two similar app stores don't clash and compete on your system, manage Flatpaks using the Bazaar store.
Enable Flatpaks on your system
Install the flatpak package on the command line:
sudo apt install flatpak
Enable the Flathub repository:
flatpak remote-add --if-not-exists flathub https://dl.flathub.org/repo/flathub.flatpakrepo
Restart your system for all changes to take effect.
Install the Bazaar app store:
flatpak install flathub io.github.kolunmi.Bazaar
Now you can open Bazaar from your applications menu. Use it to browse, install and manage other Flatpak applications.
You can also browse the Flathub website. When you click Install, Bazaar opens on your system and installs the selected application for you.