Install gir1.2-flatpak-1.0 by entering the following commands in the terminal:
sudo apt update sudo apt install gir1.2-flatpak-1.0
Description:
Application deployment framework for desktop apps (introspection)
Flatpak installs, manages and runs sandboxed desktop application bundles. See the flatpak package for a more comprehensive description. . This package can be used by other packages using the GIRepository format to generate dynamic bindings for libflatpak0.
Homepage: http://flatpak.org/
Version: 0.11.3-3
Section: universe/introspection