GTK4 themes awareness and namespace

With GNOME 40 having just dropped, and GTK4 requiring a new theme format, org.gtk.Gtk3theme.* themes shouldn’t work on GTK4 apps, and giving that I’m the maintainer of numerous theme packages, I was wondering if flatpak is already GTK4 “aware” and what will be the namespace for GTK4 themes (org.gtk.Gtk4theme.* I suspect)?