This layout mimics the default KBD 75% ANSI 1u layout with a few mac-friendly tweaks. Because Mac OS uses a unique keycode
for the Function key and only recognizes that keycode from keyboards registered with an Apple vendor ID (see here for more info),
this layout uses custom macros and F-keycodes (F12, F13, etc) to provide Mac hotbar functionality (Print Screen, Launchpad, etc...) and maps the
Fn key to the QMK momentary layer _FN (layer index 3) so it is listed as MO(3).