/usr/share/doc/libelmersolver-dbg/changelog.Debian.gz is in libelmersolver-dbg 6.1.0.svn.5396.dfsg-2ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libelmersolver-dbg/../libelmersolver-6.1/changelog.Debian.gz