[Level] 1 [Preserves] 
Preserves the XML Information Set Level 1 defines the class of candidates that preserve the XML Information Set data model. The XML Information Set preserves more of the information represented in the document type declaration and internal subset than the XPath 1.0 data model but not all information, such as attribute and element declarations, is preserved. The [all declarations processed] property of the Document Information Item is not, strictly speaking, part of the Infoset [XML Infoset] and therefore does not need to be preserved. NOTE: A candidate can fully support level 1, level 2, and the preservation of the complete internal subset by including and encoding the internal subset as a string, thereby leaving it up to the decoder to optionally process it.