/usr/lib/x86_64-linux-gnu/libgstallocators-1.0.so.0 is in libgstreamer-plugins-base1.0-0 1.8.0-1ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libgstallocators-1.0.so.0.800.0