/usr/lib/x86_64-linux-gnu/libcec.so is in libcec-dev 4.0.1+dfsg1-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libcec.so.4
/usr/lib/x86_64-linux-gnu/libcec.so.4