/usr/lib/libcoyotl.so is in libcoyotl-dev 3.1.0-6.2+b1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/libcoyotl-3.1.so.4.0.0
/usr/lib/libcoyotl-3.1.so.4.0.0