The header segment contains a number of pieces of information that are used to define the internal schema of the file these are used by the serialization and deserialization routines to know how to call the elements.

Name	Type	Description
Source	BYTE	Describes how the file was created
Encoding	BYTE	Describes how strings in the file are encoded (default is UTF8)
Namespaces	NSCOLLECTION	Collection with the details of all the namespaces
Tags	TAGCOLLECTION	Collection containing a mapping of tag id's through to name and schema