XPointer is the syntax you use for the most general addressing of parts of an XML object [XPointer]. When an HTTP URI references XML, any fragment specifier to select a portion of the XML is written in XPointer syntax. XPointer can also be called explicitly to extract a subset of data (see Chapter 19). Note that XPointer does not include any way to point into the DTD or XML declaration for a document.
XPointer extends XPath so that you can use it in the following ways:
As a fragment identifier in a URI reference
To locate information by string matching
To address points and ranges within XML
In XML Security URIs, you should rarely encounter ...