Fluka's underlying physics manual?

Dear colleagues,

Is there any attempt to establish a physics manual for Fluka?
By the way, there are some strange questions about underlaying details of
this code.
For example, little is known about the thermal neutrons scattering laws, and
even the "format" of cross sections used (not only for low-neutrons).
However, The lack of such details acts as a barrier in front of effective
use of the code in depth.

My last question is about release of the source code? Is there any plan to
distribute among users? I remember that some years ago it was going to
publish, but it has been maintained limited to CERN and INFN colleagues.

Best Regards

-- 
Ali Koosha