/usr/share/doc/libopenscenegraph100v5/changelog.Debian.gz is in libopenscenegraph100v5 3.2.1-7ubuntu4.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libopenscenegraph100v5/../libopenthreads20/changelog.Debian.gz