It's the language that Microsoft's opponents in Europe claim the company is using as a possible proprietary bypass of HTML. But now, that opposition will have to face the fact that nearly every scintilla of detail about XAML is in the public record.

The second bit of news emerging from Microsoft today on the interoperability front comes from its release of complete documentation for its existing 2006 implementation of Extensible Application Markup Language (XAML): both the object mapping specification and the vocabulary specification for Windows Presentation Foundation (WPF). (Complete ZIP file with both specs available here)

XAML is an XML document type that refers to Microsoft's preferred organization for data produced by the engines of applications. The company's own best example of XAML comes from WPF, which uses information formatted in XAML to generate displays and controls for .NET applications. It's the distancing of the application engine from the display component by the length of a global network, that's the basic principle behind Silverlight.

Not that today's publication of these specifications necessarily makes the job of creating an independent implementation of WPF via XAML easy; in fact, the 548-page vocabulary specification is extensive and replete. But if someone were to try, they might have a hard time finding anything missing from today's release.

Perhaps more importantly, Microsoft is pledging, under its Open Specification Promise, that it won't file any claims against anyone who producing and selling that implementation -- provided it follows the specification rather than attempting to amend it.

That said, in the preface material, Microsoft acknowledges that the documentation itself is in a state of flux. "This documentation is preliminary documentation for these formats," the new boilerplate text reads. "Since the documentation may change between this preliminary version and the final version, there are risks in relying on preliminary documentation. To the extent that you incur additional development obligations or any other costs as a result of relying on this preliminary documentation, you do so at your own risk."