/usr/share/common-lisp/systems/xlunit.asd is in cl-xlunit 0.6.3-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/common-lisp/systems/../source/xlunit/xlunit.asd
/usr/share/common-lisp/systems/../source/xlunit/xlunit.asd