I found strange thing with clang-tidy in official clang release. Bunch of libraries from clang-tidy are included in official releases. But corresponding header files are not so it looks like these libraries are completely unusable. Is there a reason for this?
I think having clang-tidy available in libraries + headers for building own clang-tidy like tools is convenient for separating checks from upstream and private ones.
List of libraries in official clang 9 destitution: