Look, up in the sky, it's a gui, it's a browser, its WPF/E  (WpFe) ...

No, just little ol' me, XaMl. 

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An important part of XaMl is XPS, the PDF killer. Its design principles according to blogger Andy Simonds are: Open Format, Trustworthy, High Fidelity Graphics, Platform for Innovation, Integrated Solution.

Note MicrosoftOffice version 12 will stored files natively as OpenXml format, and have "export" to XPS and other formats.