This file is indexed.

/lib/modules/4.13.0-26-lowlatency/build is in linux-headers-4.13.0-26-lowlatency 4.13.0-26.29~16.04.2.

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

It is a symlink to /usr/src/linux-headers-4.13.0-26-lowlatency