/usr/share/doc/libdune-grid-glue-dbg/changelog.Debian.gz is in libdune-grid-glue-dbg 2.4.0-1build1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libdune-grid-glue-dbg/../libdune-grid-glue-dev/changelog.Debian.gz