/usr/share/doc/gtk2-engines-qtcurve/changelog.Debian.gz is in gtk2-engines-qtcurve 1.8.18+git20160112-0cd6aae-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/gtk2-engines-qtcurve/../libqtcurve-utils2/changelog.Debian.gz