One of the reasons for creating Tribblix in the first place was that there really wasn't any documentation on how OpenSolaris (as was) was built. I wanted to understand that, so had to work it out essentially from scratch. I soon worked out that there were ways to do it better, and Tribblix is still here something like 15 years later.
That tracks:) On which note... Any chance you wrote it down? Because I'm also quite interested in knowing how to do that, and as you note the documentation is...