Let’s be honest, most of us are not C++ gurus, it takes around 15 Years, to become god like at C++, we do understand the functionality of C++ to a level till it gets complicated, after that we have to have some proper documentation.
Complicated flying api code is also a problem that is part of some complicated module like the AI module, you have to dig into the module, spend time to understand it because there is no C++ documentation.
The C++ documentation does not address an advanced C++ user, it only addresses the good and the expert since it is very mechanical, I find the C++ doc page very rude , no tutorials, no examples, just what coresponds to what as a list.