/usr/share/sawfish/lisp/shade-stack.jl is in sawfish-lisp-source 1:1.11.90-1.1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/sawfish/lisp/sawfish/wm/ext/shade-stack.jl
/usr/share/sawfish/lisp/sawfish/wm/ext/shade-stack.jl