/usr/lib/x86_64-linux-gnu/libffi.so.6 is in libffi6 3.1~rc1+r3.0.13-12.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libffi.so.6.0.1
/usr/lib/x86_64-linux-gnu/libffi.so.6.0.1