Some applications, including Flatpak, use XDG Desktop Portals to provide access to various system interfaces, including file open and save dialogs, the clipboard, screencasting, opening URLs, and more.
XDG Desktop Portals require a user D-Bus session
xdg-desktop-portal and one or
|Provides most common and GNOME-specific interfaces (GTK+ UI)|
|Provides most common interfaces (GTK+ UI)|
|Provides most common and KDE-specific interfaces (Qt/KF5 UI)|
|Only provides a file chooser (based on libfm-qt)|
|Only provides a file chooser|
|Only provides a screenshot and screencasting interface for wlroots compositors|
If unsure what to choose,
xdg-desktop-portal-gtk is a good default choice.
In most cases, the default configuration, located at
/usr/share/xdg-desktop-portal/portals.conf, should suffice. If necessary, this
configuration can be overridden for specific desktop environments and portal
interfaces by creating
the system or user level as described in