This is a rough 'table of contents' overview of how the main code components are organised:
renderdoc/
CMakeLists.txt ; The cmake file, will recurse into subdirectories to build them
renderdoc.sln ; VS2015 solution for windows building
renderdoc/
3rdparty/ ; third party utilities & libraries included
drivers/ ; API-specific back-ends, can be individually skipped/removed
... ; everything else in here consists of the core renderdoc runtime
renderdoccmd/ ; A small C++ utility program that runs to do various little tasks
renderdocshim/ ; A tiny C DLL using only kernel32.dll that is used for global hooking
qrenderdoc/ ; The Qt UI layer built on top of renderdoc/
docs/ ; source documentation for the .chm file or http://docs.renderdoc.org/
util/ ; folder for utility/support files - e.g. build scripts, installers, CI config