/usr/share/doc/libgssapi3-heimdal/changelog.Debian.gz is in libgssapi3-heimdal 1.6~git20131207+dfsg-1ubuntu1.2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libgssapi3-heimdal/../libroken18-heimdal/changelog.Debian.gz