/usr/lib/x86_64-linux-gnu/libcwidget.so is in libcwidget-dev 0.5.17-4ubuntu2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libcwidget.so.3.0.0
/usr/lib/x86_64-linux-gnu/libcwidget.so.3.0.0