/usr/share/common-lisp/systems/mcclim-tree-with-cross-edges.asd is in cl-mcclim 0.9.6.dfsg.cvs20100315-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/common-lisp/systems/../source/mcclim/Experimental/tree-with-cross-edges/mcclim-tree-with-cross-edges.asd