/usr/lib/linux-tools/4.15.0-23-generic/x86_energy_perf_policy is in linux-tools-4.15.0-23-generic 4.15.0-23.25.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/linux-tools/4.15.0-23-generic/../../linux-tools-4.15.0-23/x86_energy_perf_policy