Internet Archive ARC (web archive) (.arc)

def is_arc(file_path: str) -> bool:
    """Check if file is a valid ARC by magic bytes."""
    signature = bytes([0x66, 0x69, 0x6C, 0x65, 0x64, 0x65, 0x73, 0x63, 0x3A, 0x2F, 0x2F])
    with open(file_path, "rb") as f:
        return f.read(11) == signature

function isARC(buffer: Buffer): boolean {
  const signature = Buffer.from([0x66, 0x69, 0x6C, 0x65, 0x64, 0x65, 0x73, 0x63, 0x3A, 0x2F, 0x2F]);
  return buffer.subarray(0, 11).equals(signature);
}

func IsARC(data []byte) bool {
    signature := []byte{0x66, 0x69, 0x6C, 0x65, 0x64, 0x65, 0x73, 0x63, 0x3A, 0x2F, 0x2F}
    if len(data) < 11 {
        return false
    }
    return bytes.Equal(data[:11], signature)
}