Will there be any documentation for the "XBF" binary XAML format?

Question

At Build, it was announced that Xaml will be compiled. This affects my work quite a bit. We do work reading and modifying XAML files inside of Appx packages. So, I downloaded the previews and made a quick sample application and indeed, no XAML file in sight. Instead, I have this strange .xbf file for each XAML page. Using a hex editor I can see familiar things like XML namespaces for XAML, but this does not appear to be anything like BAML, so there is basically no documentation for it. A completely new format.

Has (or will) Microsoft release some form of documentation about this new binary XAML format?

Answer 1

There are no plans to provide documentation on the format. An API exists to create the format. If you are a tool or some other intermediate process, you can instruct your developers to turn off XBF generation (in the proj file DisableXbfGeneration=true) and then do your intermediate work, then you'd be responsible for generating the XBF in your process.

Answer 2

Microsoft will eventually have to publish the details or else face the fact that they once again have an unfair advantage with their tooling relative to other developer tool vendors. Until then, reflection is your best friend, but they did seem to try a little harder to make this difficult to dig into for obvious reasons.