A set of merge requests were opened that would effectively drop X.Org (X11) session support for the GNOME desktop and once that code is removed making it a Wayland-only desktop environment.
Going along with Fedora 40 looking to disable the GNOME X11 session support (and also making KDE Plasma 6 Wayland-only for Fedora), upstream GNOME is evaluating the prospect of disabling and then removing their X11 session support.
Some concerns were raised already how this could impact downstream desktops like Budgie and Pantheon that haven’t yet fully transitioned over to Wayland. In any event we’ll see where the discussions lead but it’s sure looking like 2024 will be the year that GNOME goes Wayland-only.
Sway is based on wlroots and therefore does not need to implement the complete Wayland specification itself. Many other Wayland window managers are also based on wlroots and therefore share a common base (compositor).
Furthermore Sway’s git repo has activity up to a couple of days ago: https://github.com/swaywm/sway/commits/master