Door Knocker is a free and open source portal application for Linux. Using Door Knocker, you can check availability of all portals provided by xdg-desktop-portal. It shows all available and unavailable portals. It is released under GNU General Public License v3.0.
Install Door Knocker on Ubuntu
You can install Door Knocker via below flatpak install command. Open the terminal app (ctrl+alt+t) and run below command. It will install the latest version of Door Knocker on your system.
flatpak install flathub xyz.tytanium.DoorKnocker
And open the Door Knocker app using below commands.
flatpak run xyz.tytanium.DoorKnocker
If you don’t have then first install flatpak and flathub on your system using below link. And restart your system after the installation.
You can also uninstall it using below commands.
flatpak uninstall flathub xyz.tytanium.DoorKnocker
[OR]
sudo flatpak uninstall flathub xyz.tytanium.DoorKnocker