/usr/share/sawfish/lisp/idesk.jl is in sawfish-lisp-source 1:1.11-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/sawfish/lisp/sawfish/wm/prg/idesk.jl
/usr/share/sawfish/lisp/sawfish/wm/prg/idesk.jl