/usr/lib/x86_64-linux-gnu/libkwin.so.5 is in kwin-common 4:5.5.5-0ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libkwin.so.5.5.5
/usr/lib/x86_64-linux-gnu/libkwin.so.5.5.5