If I'm reading the announcement right, it's the default for GNOME alone, which makes sense: GNOME now defaults to Wayland and the other desktops default to X,

If I'm reading the announcement right, it's the default for GNOME alone, which makes sense: GNOME now defaults to Wayland and the other desktops default to X, Debian has no reason to second-guess them. Worse, changing the defaults in this area would be a fork in all but name.