/usr/share/doc/libotbiobsq-6.4-1/changelog.Debian.gz is in libotbiobsq-6.4-1 6.4.0+dfsg-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libotbiobsq-6.4-1/../libotbcommon-6.4-1/changelog.Debian.gz