qmk_firmware/keyboards/boardsource/3x4/info.json

{
    "keyboard_name": "boardsource 4x3",
    "url": "https://boardsource.xyz",
    "maintainer": "boardsource",
    "width": 4,
    "height": 3,
    "layouts": {

        "LAYOUT": {

            "layout": [
                { "label": "K01", "x": 0, "y": 0 },
                { "label": "K02", "x": 1, "y": 0 },
                { "label": "K03", "x": 2, "y": 0 },
                { "label": "K04", "x": 3, "y": 0 },

                { "label": "K05", "x": 0, "y": 1 },
                { "label": "K06", "x": 1, "y": 1 },
                { "label": "K07", "x": 2, "y": 1 },
                { "label": "K08", "x": 3, "y": 1 },

                { "label": "K09", "x": 0, "y": 2 },
                { "label": "K10", "x": 1, "y": 2 },
                { "label": "K11", "x": 2, "y": 2 },
                { "label": "K12", "x": 3, "y": 2 }
            ]
        }
    }
}