This file is indexed.

/lib/modules/3.19.0-51-lowlatency/build is in linux-headers-3.19.0-51-lowlatency 3.19.0-51.58~14.04.1.

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

It is a symlink to /usr/src/linux-headers-3.19.0-51-lowlatency