Search for package

flatpak --user search octave

Install package

flatpak --user install flathub org.octave.Octave

flatpak --user list

flatpak --user update

List only installed applications, without runtimes:

flatpak list --app

List only installed runtimes, without applications:

flatpak list --runtime

Remove un-used runtime libraries:

flatpak uninstall --unused

Remove application and all its data:

flatpak uninstall --delete-data org.Gnome.Todo

Fix broken package:

flatpak repair