XDG Desktop Portal

A portal frontend service for Flatpak and other
desktop containment frameworks.

xdg-desktop-portal works by exposing a series of D-Bus interfaces known as
portals under a well-known name (org.freedesktop.portal.Desktop) and object
path (/org/freedesktop/portal/desktop).

The portal interfaces include APIs for file access, opening URIs, printing
and others.

Documentation about the Common Conventions, as well as documentation for
App Developers, Desktop Developers and Contributors can be found
here.