xdpss creates a Xdg Desktop Portal ScreenCast Session and outputs the
PipeWire node of the stream.
On Ctrl-C, it closes the session.
Get the PipeWire node number,
use gstreamer to mirror the screen
(example/xdpss-mirror.sh mirror),
record the screen
(example/xdpss-mirror.sh record record.mp4)
or launch a rootful XWayland window with screen sharing
(example/xwayland-rootful-openbox.sh).