The binary encoding of Unions has a C/C++ example with following text:
"In the C/C++ example above, the Selector and Value are semantically coupled to form a union."

It should be "...Field1 and Field2 are semantically coupled to form a union." instead.

In addition, the next sentence says
"The order of the fields does not matter."

I think this is quite misleading, because while it is true for the semantics of the union, Part 6 and this text is about how the unions are encoded, and for the encoding, the order of the union fields does matter, because it determines the value of the encoded switch field.