/usr/lib/x86_64-linux-gnu/libcplui.so is in libcpl-dev 6.4.1-5.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libcplui.so.20.4.1
/usr/lib/x86_64-linux-gnu/libcplui.so.20.4.1