My apologies if this question has been asked
before in this list. What would be the most accurate doc that explains
in detail the design and implementation of Fiasco.OC internals?
when you say "most accurate" I'm tempted to reply "the source code".
Since Fiasco.OC's interface is still a moving target, the best docu you
can find is the L4RE documentation:
in the Base API section in Modules. Currently, we don't have something
like an "internals" documentation but perhaps we can help you out with
some more specific questions. Which part are you interested in?