Different authors -- post and repo -- it would appear. But between the example.cpp and unittest.cpp, there is quite a bit there; if you're not familiar with Flaks, it is a very simple web "framework" that basically just provides request, routing, and response primitives. This library also includes a JSON lib, but Flask gets that from Python's batteries.

Also, Flask was created as a joke; it obviously took off; but there's something there about not taking it super super serious.