/usr/share/doc/libcephfs1-dbg/changelog.Debian.gz is in libcephfs1-dbg 0.80.11-0ubuntu1.14.04.3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libcephfs1-dbg/../libcephfs1/changelog.Debian.gz