For the books
For those curious, this is what Questia used to look like:
Questia was started in 2014, and at some point the following tools/libraries were used: C++0x/C++11/C++14/C++17, MinGW Makefiles, CMake, Conan, git, Cryptopp, SFML, SDL2, UnitTest++, GoogleTest, GLFW, Glad, Travis CI, AppVeyor. If you wanted to look at the code (please don't), it's archived in the GitHub organization repository.