/usr/lib/x86_64-linux-gnu/liburcu.so is in liburcu-dev 0.9.1-3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/liburcu.so.4.0.0
/usr/lib/x86_64-linux-gnu/liburcu.so.4.0.0