XML Application versus XML Software

An XML application is a class of XML documents defined by a schema, specification, or some group of rules. For example, Scalable Vector Graphics (SVG), XHTML, MathML, GedML, XSL Formatting Objects, and DocBook are all XML applications. The simple language I invented last Thursday to categorize my comic book collection is also an XML application even though it doesn't have a DTD, schema, or even a specification. An XML application is not a piece of application software that somehow processes XML, such as the XMLSPY editor, the Mozilla web browser, or the XEP XSL-FO to PDF converter.