@gnomon it's a shield/hat for any Uno R3 compatible board. Lots of dev kits, etc expose that, so it can be used as an easy drop on kit for developing ZMK. Either new features you're using debugger to work on, or evaluating new hardware platforms, e.g. rp2040.

Supports:
* Matrix or direct wire switches (by just adding a jumper)
* OLED
* ec11 encoder
* Single color backlight
* Underglow
* Per-key RGB
* TRRS jack with a few different connection options

Mix of current and future hardware.