/usr/lib/x86_64-linux-gnu/libfcl.so is in libfcl-dev 0.5.0-5.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libfcl.so.0.5
/usr/lib/x86_64-linux-gnu/libfcl.so.0.5