/usr/lib/x86_64-linux-gnu/libluajit-5.1.so.2 is in libluajit-5.1-2 2.0.4+dfsg-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libluajit-5.1.so.2.0.4
/usr/lib/x86_64-linux-gnu/libluajit-5.1.so.2.0.4