qmk_firmware/data/templates/base/info.json

{
    "keyboard_name": "%KEYBOARD%",
    "url": "",
    "maintainer": "%YOUR_NAME%",
    "width": 3,
    "height": 2,
    "layouts": {
        "LAYOUT": {
            "layout": [
                {"label": "k00", "x": 0, "y": 0},
                {"label": "k01", "x": 1, "y": 0},
                {"label": "k02", "x": 2, "y": 0},

                {"label": "k10", "x": 0, "y": 1, "w": 1.5},
                {"label": "k12", "x": 1.5, "y": 1, "w": 1.5}
            ]
        }
    }
}