/usr/share/doc/ginac-tools/changelog.Debian.gz is in ginac-tools 1.7.4-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/ginac-tools/../libginac6/changelog.Debian.gz
/usr/share/doc/ginac-tools/../libginac6/changelog.Debian.gz