Currently, when the user installs flatpak only xdg-desktop-portal is installed. This results in some issues with flatpaks like flatpak apps not being able to open links in a flatpak browser.
This issue is also encountered on a new installation (Budgie Plasma), see : Discussion
According to that user the same is maybe not needed for xdg-desktop-portal-kde but I did not test that.
See T7949 and if xdg-desktop-portal-gtk becomes a dependency of xdg-desktop-portalplasma user will get it while they actually need xdg-desktop-portal-kde
Sorry, missed that issue. But according to the discussion it is also not included on new installations (which I think have flatpak by default?) maybe it would make sense to add it there at least?
Technically it's only the Budgie and MATE images that would need it, as it is a dependency of GNOME Shell (and thus not required for Solus GNOME Edition). I'll get it added to the Budgie and MATE images and the kde portal package to the Plasma one.