/usr/lib/linux-tools/4.13.0-39-lowlatency/cpupower is in linux-tools-4.13.0-39-lowlatency 4.13.0-39.44~16.04.1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/linux-tools/4.13.0-39-lowlatency/../../linux-hwe-tools-4.13.0-39/cpupower