/usr/lib/libunwind-x86_64.so is in libunwind7-dev 0.99-0.3ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/libunwind-x86_64.so.7.0.0
/usr/lib/libunwind-x86_64.so.7.0.0