/usr/share/doc/libtopmenu-server-gtk2-dbg/changelog.Debian.gz is in libtopmenu-server-gtk2-dbg 0.2.1+git20151210.8c6108f-3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libtopmenu-server-gtk2-dbg/../libtopmenu-server-gtk2-0/changelog.Debian.gz