/usr/lib/x86_64-linux-gnu/libcplcore.so is in libcpl-dev 6.6.1-1build1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libcplcore.so.20.6.1
/usr/lib/x86_64-linux-gnu/libcplcore.so.20.6.1