qmk_firmware/keyboards/primekb/prime_e/std/keyboard.json

{
    "keyboard_name": "Prime_E",
    "usb": {
        "pid": "0x0051",
        "device_version": "0.0.1"
    },
    "features": {
        "backlight": true
    },
    "backlight": {
        "pin": "B7",
        "levels": 5
    }
}