Primary Magic Base - Int32
  Base Primary Magic.

Primary Magic - PrimaryMagicBaseAddress - (IndexOffset + 32)
  Used to find Tag Meta Offsets in memory, and to calculate the Tag Start.

Tag List Entry Count - Int32
  Number of Tag Classes. See Tag List Definition.

Object Index Base Address - Int32
  Base address to the Object Index.

Object Index - ObjectIndexBaseAddress - PrimaryMagic
  Points to an Index of Tags.

Scenario Identifier - Int32
  Identifier of the Scenario tag.

Globals Identifier - Int32
  Identifier of the Globals tag.

Unknown - Int32?
  Unknown Purpose.

Tag Count - Int32
  Number of Tags in the map.

Tag Start Block - Chars(4)
  4 reversed letters defining the Tag Start.

Secondary Magic Base Address - Raw Meta Offset of the Globals(matg) Tag.

Secondary Magic - SecondaryMagicBaseAddress - (IndexOffset + IndexSize)
  Used to calculate the Meta offset of tags, and the translation of Reflexives.

Notes:
  The Index has a constant Header Length of 32.

  Index Layout:
    - Header
    - Tag List
    - Object Index

  Tag List:
    This list contains all used tags in the map file, and defines their object hierarchy. 
    This allows the engine to know for example, that all vehicles are a sub class of the 
    unit class, which is a sub class of the object class. I believe the wildcard tags are 
    used as a way of using the primary tag without its parents, though this is just speculation. - Iron Forge

  Object Index:
    The object index is a recursively-constructed collection defining all objects in the map.
    The objects identifier is defined here, which is used to reference the object from all other
    areas of the map file. The identifier is composed of two short values, each are incremented
    equally throughout the index. The meta offset is a secondary magic offset which points to
    the beginning of the objects meta. - Iron Forge