/// This encoding matches GB18030-2005 except the two-byte sequence 0xA3 0xA0
/// maps to U+3000 for compatibility with existing Web content. As a result,
/// this encoding can represent all of Unicode except for the private-use
/// character U+E5E5.
///
/// [Index visualization for the two-byte sequences](https://encoding.spec.whatwg.org/gb18030.html),
/// [Visualization of BMP coverage of the two-byte index](https://encoding.spec.whatwg.org/gb18030-bmp.html)
///
/// This encoding matches the Windows code page 54936.