/usr/lib/x86_64-linux-gnu/libcctz.so is in libcctz-dev 2.2+dfsg1-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libcctz.so.2
/usr/lib/x86_64-linux-gnu/libcctz.so.2