This file is indexed.

/lib/modules/3.16.0-6-amd64/build is in linux-headers-3.16.0-6-amd64 3.16.56-1+deb8u1.

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

It is a symlink to /usr/src/linux-headers-3.16.0-6-amd64