Install xdg-desktop-portal-kde by entering the following commands in the terminal:
sudo apt update sudo apt install xdg-desktop-portal-kde
Description:
backend implementation for xdg-desktop-portal using Qt
xdg-desktop-portal-gtk provides a Qt implementation for the desktop-agnostic xdg-desktop-portal service. This allows sandboxed applications to request services from outside the sandbox using KDE GUIs (app chooser, file chooser, print dialog) or using KDE services (session manager, screenshot provider).
Homepage: https://cgit.kde.org/xdg-desktop-portal-kde.git/
Version: 5.12.4-0ubuntu2
Section: universe/kde