/usr/share/doc/icedtea-7-jre-cacao/changelog.Debian.gz is in icedtea-7-jre-cacao 7~u3-2.1.1~pre1-1ubuntu2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/icedtea-7-jre-cacao/../openjdk-7-jre-headless/changelog.Debian.gz