Overlay for window managers so you can manipulation windows via keyboard and treat windows like floating tiles. They float and can cover each other, but keyboard commands slot them in to specific spots and resize accordingly. It's all very fluid.
This is the stock QMK firmware layout for a planck rev 6, but with the steno layer replaced by the keys specified in the Gemini protocol. It also has a couple small changes that enable that mode to talk the protocol to your computer.