/usr/lib/x86_64-linux-gnu/liblttng-ust-pthread-wrapper.so is in liblttng-ust-dev 2.9.0-2+deb9u1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/liblttng-ust-pthread-wrapper.so.0.0.0