GNOME 3.10 has many Wayland improvements from Mutter work to the GNOME Shell interface to the GTK+ tool-kit. The latest GNOME Wayland improvement to talk about is rather subtle but important: GNOME Shell is now being built in two binaries, one for X11 and one for Wayland.
The support was committed this week to build two separate binaries for X11 and Wayland. The gnome-shell binary is built against libgnome-shell while gnome-shell-wayland is built against the libgnome-shell-wayland library. These libraries then link against libmutter and libmutter-wayland, respectively.
This fundamental build change makes it easy now to run a single build process and end up with supported binaries for X11 and Wayland, which in turn can then be easily run by end-users. This GNOME Shell build change happened with this Git commit. Additional reference can be found by this GNOME.org BugZilla entry.