Corel Presentation Exchange (.cmx)

def is_cmx(file_path: str) -> bool:
    """Check if file is a valid CMX by magic bytes."""
    signature = bytes([0x52, 0x49, 0x46, 0x46])
    with open(file_path, "rb") as f:
        return f.read(4) == signature

function isCMX(buffer: Buffer): boolean {
  const signature = Buffer.from([0x52, 0x49, 0x46, 0x46]);
  return buffer.subarray(0, 4).equals(signature);
}

func IsCMX(data []byte) bool {
    signature := []byte{0x52, 0x49, 0x46, 0x46}
    if len(data) < 4 {
        return false
    }
    return bytes.Equal(data[:4], signature)
}