/usr/share/doc/libservlet2.5-java-doc/changelog.Debian.gz is in libservlet2.5-java-doc 6.0.35-1ubuntu3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libservlet2.5-java-doc/../libservlet2.5-java/changelog.Debian.gz