/usr/share/doc/linux-tools-4.15.0-1024-gcp/changelog.Debian.gz is in linux-tools-4.15.0-1024-gcp 4.15.0-1024.25.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/linux-tools-4.15.0-1024-gcp/../linux-gcp-tools-4.15.0-1024/changelog.Debian.gz