What is the default desktop environment in dom0 planned to be used in future versions of Qubes OS? @likeafox has mentioned that a migration is planned, more specifically from Xfce to the KDE.
This is relevant especially to developers of GUIs of dom0 apps.
Research I have done:
Installed Qubes OS 4.3 testing ISO. The DE is Xfce.
Checked the docs. It says a migration to GNOME is planned, however this info is already in the docs since at least Mar 9, 2016 and thus likely outdated.
It all revolves around wayland support. You can track GUI domain developments in this github project. Another thing to consider is that setup with dedicated sys-gui may or may not have GUI in dom0, but I’m not sure about this.
It seems they aren’t considering it until it “actually seems like a good fit”. However, that last comment was made a while ago, and I think COSMIC will definitely be a good fit once it hits stable