qmk_firmware/keyboards/handwired/technicpad/keymaps/via/keymap.json

{
    "keyboard": "handwired/technicpad",
    "keymap": "via",
    "config": {
        "features": {
            "via": true
        }
    },
    "layers": [
        ["KC_A", "KC_B", "KC_C", "KC_D"]
    ],
    "layout": "LAYOUT"
}