We closely follow the wlroots contributing guidelines where possible. Please see that document for more information.
Useful tools include dbus-monitor to watch requests being made,
and dbus-send and the similar busctl call for manual dbus calls.
You can test the integration with the portal-test Flatpak app.
Alternatively you can trigger it with trigger-screen-shot.py and xdp-screen-cast.py.
xdg-desktop-portal will read the XDG_DESKTOP_PORTAL_DIR environment variable for an alternate path for *.portal files. This can be useful when testing changes to that portal file, or for testing xdpw without installing it. This feature is undocumented and shouldn't be relied on, but may be helpful in some circumstances.