Anyone have good information on general OpenFirmware development?

[bill gate via Darwin-dev]

Hello, I was wondering if anyone here knew of good documentation sources
(besides the IEEE standard document) for writing OpenFirmware software.
Sorry if this is the wrong list to post this to, I can move further discussion
elsewhere if need be.

Best wishes,
Niko Chow-Stuart
CEO Real Microsoft, LLC.

Sent with my Lumia Windows Phone