Reading the layouts

The layout of a structure is given by a table with a row per field:

Offset: Offset of the field, counted from the beginning of the structure, header included, the way the specification counts it.
Version: Version of the specification the field appears in, e.g. 2.1+. The data of the platforms following an older version ends before the field.
Name: Name of the field.
Length: Size of the field: BYTE, WORD, DWORD and QWORD stand for 8-, 16-, 32- and 64-bit values, stored in the little-endian byte order. n BYTEs gives the size through the number n a field before it holds, e.g. 2n BYTEs for n values of a WORD each, and Varies stands for a field whose size depends on the data.
Value: Kind of the value the field holds: NUMBER for a number, ENUM for one of the values an enumeration defines, BITFIELD for a set of bits, STRING for the number of a string of the structure, HANDLE for the handle of another structure, ADDRESS for an address in memory or in the I/O space, and SPEED for a speed, in the units the description gives. A number stands for the fixed value of the field, e.g. the type of the structure, and Varies for a value the description explains.
Description: Meaning of the field.

Values of the enumerations are given by tables of their hexadecimal and decimal values and their meanings, and the bits of the sets of bits by tables of their positions and meanings.