[Rdo-list] What encourages good software design in openstack?

I have been scouring Openstack artifacts to find examples of what encourages good software design in its system architecture and code. The info will be used in teaching university students. I suppose it would be good for new developers of the community too. I found your blueprints and bugs and code reviews, but cant piece together how good architecture and design are encouraged via process and/or documents. Code standards? Design standards? I see the Design Summits, but have not yet found design recommendations or a process that new code goes through to ensure decent design rules of thumb. Does it come from Developers experience, or are there some sort of artifacts to point at? I am not as interested in specific examples of good design (though please send me whatever), but more a meta of that. What encourages or describes good design in Openstack? Thanks, -Nick Yeates