This library implements a number of existing standards related to
markup languages, including the XML standard, name spaces in XML, XML
Base, RFC 2396, XPath, XPointer, HTML4, XInclude, SGML catalogs, and
XML catalogs. In most cases, libxml tries to implement the
specification in a rather strict way. To some extent, it provides
support for the following specifications, but does not claim to
implement them: DOM, FTP client, HTTP client, and SAX.