The root element can be any element that is not in a DeltaXML namespace. It contains the elements that are used to retain the: XML declaration; the DOCTYPE; and the comments and processing instructions that are outside the body in the specified order. Note that the original document elements are also included in this sequence. The XML declaration can be retained as a childless element, where the version and encoding data can be encoded in attributes. Note that the standalone attribute is not retained as this cannot currently be preserved. 1.0 1.1 External references can have public and system identifiers, which can be encoded into publicId and systemId attributes. The DOCTYPE and its internal subset data can be retained in a preserve:doctype element, where: the name attribute is used to specify the root element's name; the optional external reference attributes are used to identify the element's DOCTYPE specification; and its child elements are used to retain the optional internal subset data. The process instruction and comments block for retaining PIs and comments outside the body of the document. It can appear in one of three locations, before the DOCTYPE (or document body), between the DOCTYPE and document body, and after the document body. These regions are identified by the BEFORE_DTD, AFTER_DTD, and AFTER_BODY labels respectively. BEFORE_DTD AFTER_DTD AFTER_BODY A processing instruction can be retained by creating an element in the http://www.deltaxml.com/ns/processing-instructions namespace, where the element name is the same as the processing instructions tag, and the element content is the same as the processing instructions content. preserve An entity reference can be retained by creating an element in the http://www.deltaxml.com/ns/entity-references namespace, where the element name is the same as the entity's name, and the optional element content is the same as the entity's content (i.e. replacement text). Further, entity references within the internal subset can indicated that they are parameter references by setting the parameter attribute. Note that it is possible for the replacement text to contain entity references. no yes A comment can be retained by enclosing its contents in a preserve:comment element. preserve A CDATA section can be retained by enclosing its contents in a preserve:cdata element. A body element is any foreign element, DeltaXML deltaV2 (difference reporting) element, or a retained comment, processing instruction, cdata, or entity reference element. A foreign body element is any element that is not in the DeltaXML namespace. It can contain any attributes and any body-element children. A deltaV2 element is used to represent all the elements in the http://www.deltaxml.com/ns/well-formed-delta-v1 namespace. These elements are used for recording the differences between the content of two (or more) deltaxml files. A DOCTYPE's internal subset can contain element, attribute, notation, entity declaration, and entity reference elements (in addition to comments and processing instructions which are currently not retained). All the internal subset declarations have a name of thing being declared, and a DeltaXML key to ensure that this thing only matches with another element of the same type and name. An element declaration can be retained in a preserve:elementDecl element whose child content model as an attribute. An attribute declaration can be retained in a preserve:attributeDecl element that uses attributes to record the associated element name, attribute type, and optionally default value. A notation declaration can be retained in a preserve:notationDecl element. An internal parsed parameter entity declaration can be retained in a preserve:internalParsedParameterEntityDecl element, where its value is recorded in a value attribute. Note that entities within the value are encoded as discussed in the Lexical Preservation Format documentation. An internal parsed general entity declaration can be retained in a preserve:internalParsedGeneralEntityDecl element, where its value is recorded in a value attribute. Note that entities within the value are encoded as discussed in the Lexical Preservation Format documentation. An external parsed parameter entity declaration can be retained in a preserve:externalParsedParameterEntityDecl element. An external parsed general entity declaration can be retained in a preserve:externalParsedGeneralEntityDecl element. An unparsed entity declaration can be retained in a preserve:unparsedEntityDecl element, whose optional notation name is contained in a notationName attribute.