/usr/share/common-lisp/source/cl-asdf/asdf.lisp is in cl-asdf 2:3.1.4-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/common-lisp/source/cl-asdf/build/asdf.lisp
/usr/share/common-lisp/source/cl-asdf/build/asdf.lisp