/usr/lib/kde4/plugins/script/libkrossqtsplugin.so.4 is in kdelibs5-plugins 4:4.14.16-0ubuntu3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/kde4/plugins/script/libkrossqtsplugin.so.4.14.16
/usr/lib/kde4/plugins/script/libkrossqtsplugin.so.4.14.16