Since the Phantom is programmable, the two 1x keys could be anything. For me, both of them will be Windows keys. Later on, we may have firmware updates to get second or third layers, so one of the 2x keys could really become the Fn key to switch layers.
Blank could work for more people. Or we could do Windows, or the Cherry logo, or dig back out the original Phantom logo. I just worry that we would not have enough orders to make it work.