Flatpak is a utility for software deployment and package management for Linux. It is advertised as offering a sandbox environment in which users can run application software in isolation from the rest of the system. The Flathub is a App's repository.
Init
sudo apt install flatpak
flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
Search
flatpak search <package>
Install
flatpak install <package>
List
flatpak list <package>
Remove
flatpak remove <package>
Run
flatpak run <package>
Sandbox
flatpak override <app> --filesystem=<host, home, path>
flatpak override <app> --nofilesystem=<host, home, path>