/usr/share/doc/metacity/changelog.Debian.gz is in metacity 1:3.18.3-1ubuntu3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/metacity/../libmetacity-private3a/changelog.Debian.gz
/usr/share/doc/metacity/../libmetacity-private3a/changelog.Debian.gz