qmk_firmware/keyboards/atreus/f103/keyboard.json

{
    "matrix_pins": {
        "cols": ["B10", "B1", "B0", "A7", "A6", "B5", "B4", "B3", "A15", "A10", "A9"],
        "rows": ["A5", "A4", "A3", "A2"]
    },
    "diode_direction": "COL2ROW",
    "processor": "STM32F103",
    "bootloader": "stm32duino",
    "features": {
        "bootmagic": true
    }
}