A wireless split keyboard's firmware, from the layout up

A keymap with at least three layers, tap-hold keys and a leader key, defined as data

The engine resolves key events into HID reports with correct tap/hold timing

Split link: the right half sends raw matrix events to the left, which owns the keymap

Sleep after inactivity; wake on any key; report battery

A browser simulator that shows both halves and the resulting typed text

Per-layer RGB indication with a brightness cap for battery life

Requirements