This file is indexed.

/lib/modules/4.18.0-15-lowlatency/build is in linux-headers-4.18.0-15-lowlatency 4.18.0-15.16~18.04.1.

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

It is a symlink to /usr/src/linux-headers-4.18.0-15-lowlatency