/usr/share/doc/libgtk-3-dev/changelog.Debian.gz is in libgtk-3-dev 3.22.30-1ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libgtk-3-dev/../libgtk-3-0/changelog.Debian.gz
/usr/share/doc/libgtk-3-dev/../libgtk-3-0/changelog.Debian.gz