/usr/lib/x86_64-linux-gnu/librheolef.so is in librheolef-dev 6.7-6.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/librheolef.so.1.0.0
/usr/lib/x86_64-linux-gnu/librheolef.so.1.0.0