I am trying to locate the source code for this settings page. I want to build an annotation program using this implementation because it is very smooth.
Looks like it is in https://github.com/GNOME/gnome-control-center/tree/master/panels/wacom and possibly https://gitlab.gnome.org/GNOME/gnome-settings-daemon/tree/master/plugins/wacom too.
https://github.com/GNOME/gnome-control-center/blob/master/panels/wacom/gnome-wacom-panel.desktop.in.in has a
gnome-control-center wacom EXEC and sure enough running that launches that settings panel!