qmk_firmware_custom/keyboards/macropad/info.json

{
  "keyboard_name": "Macropad",
  "url": "",
  "maintainer": "qmk",
  "width": 3,
  "height": 3,
  "layouts": {
      "LAYOUT": {
          "layout": [{"x":0, "y":0}, {"x":1, "y":0}, {"x":2, "y":0}, {"x":0, "y":1}, {"x":1, "y":1}, {"x":2, "y":1}, {"x":0, "y":2}, {"x":1, "y":2}, {"x":2, "y":2}]
      }
  }
}