That's still a non-sequitur. As an counter-example, it's possible to write conformant C++ without using any features that aren't also in C: I am, objectively,

That's still a non-sequitur. As an counter-example, it's possible to write conformant C++ without using any features that aren't also in C: I am, objectively, not using C++ to the fullest if I'm restricting myself to functions instead of methods, char pointers instead of std::string, statically allocated arrays or pointers instead of vectors, and so on, thereby ignoring 90% of the spec. If I'm not using constexpr, for example, then I'm using one of less feature provided by the language. Constexpr, like all other modern C++ features not present in "old" C++, was invented to serve a purpose, and without it, you have to reach for more blunt, possibly more verbose and less expressive tools. In other words, many new features (such as ranges) increase expressiveness in a quantifiable manner. I may not need, for the specific program that I'm writing, the full range of features, and may not need constexpr. But that wasn't the question. Again, I'm not asking about egregious use of features of features' sake. I'm asking about examples of projects that use in a positive and not superfluous terms modern features of C++. It's not an absurd question, and your response is just obtuse (and unhelpful!).