/usr/share/doc/libpango1-ruby1.8-dbg/changelog.Debian.gz is in libpango1-ruby1.8-dbg 1.0.3-1build1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libpango1-ruby1.8-dbg/../ruby-glib2/changelog.Debian.gz