xdg-desktop-portal 1.17.x introduces a new way to select which portals will
be used for which desktop environments, modelled on mimeapps.list:
- each desktop environment should provide a file like
/usr/share/xdg-desktop-portal/ukui-portals.conf
- the filename is ${DESKTOP}-portals.conf where ${DESKTOP} is the desktop
environment's entry in $XDG_CURRENT_DESKTOP (the same as the DesktopNames
from /usr/share/{x,wayland-}sessions/*.desktop), folded to lower case
- sysadmins and users can override this via files named portals.conf or
${DESKTOP}-portals.conf in various locations like /etc/xdg-desktop-portal
and ~/.config/xdg-desktop-portal
Please see portals.conf(5) or its source code
https://github.com/flatpak/xdg-desktop-portal/blob/main/doc/portals-conf.rst
for full details.
As a backwards-compatibility mechanism, x-d-p will fall back to trying
to guess the most appropriate portals from the portals' UseIn= fields,
but it will log warnings when it does that, and anyway Debian doesn't
currently ship any portal backends that are flagged as suitable for UKUI.
Please add a ukui-portals.conf to tell x-d-p more explicitly what backends
UKUI is meant to be using by default.
For example, if the intention is to use x-d-p-gtk, the way to write that
would be:
[preferred]
default=gtk;
The desktop environment (either ukui-session-manager or some larger
metapackage) should probably also have a Recommends, or at least a
Suggests, on whatever portals would be most appropriate for it.
For an example of a more complex portal configuration, see gnome-session:
https://salsa.debian.org/gnome-team/gnome-session/-/commit/b201c9c40e3adc7bf0b1c3504bef4c8602aac31d
Thanks,
smcv