[Level] 2 [Preserves] 
Preserves the the XML Information Set and all declarations Level 2 defines the class of candidates that preserve the XML Information Set data model, as in level 1, in addition to all information that is not purely syntactic. Such additional information will include the attribute, element and entity declarations. This level covers the preservation of all information represented by an XML document but does not accede to supporting purely syntactic constructs. NOTE: A candidate can fully support level 2 by including and encoding the internal subset as a string, and thus leaving it up to the decoder to optionally process it.