/usr/share/common-lisp/systems/zs3.asd is in cl-zs3 1.2.7-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/common-lisp/systems/../source/zs3/zs3.asd
/usr/share/common-lisp/systems/../source/zs3/zs3.asd