This file is indexed.

/usr/lib/clang/4.0.1/include is in libclang-common-4.0-dev 1:4.0.1-10~deb9u2.

This file is owned by root:root, with mode 0o777.

It is a symlink to /usr/lib/clang/4.0.1/../../llvm-4.0/lib/clang/4.0.1/include