Macromedia Shockwave Flash player file (.swf)

def is_swf(file_path: str) -> bool:
    """Check if file is a valid SWF by magic bytes."""
    signature = bytes([0x43, 0x57, 0x53])
    with open(file_path, "rb") as f:
        return f.read(3) == signature

function isSWF(buffer: Buffer): boolean {
  const signature = Buffer.from([0x43, 0x57, 0x53]);
  return buffer.subarray(0, 3).equals(signature);
}

func IsSWF(data []byte) bool {
    signature := []byte{0x43, 0x57, 0x53}
    if len(data) < 3 {
        return false
    }
    return bytes.Equal(data[:3], signature)
}