/usr/share/icons/wm-icons/56x56-martys2/mouse.xpm is in wm-icons 0.4.0-10.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/icons/wm-icons/56x56-martys2/todo.xpm
/usr/share/icons/wm-icons/56x56-martys2/todo.xpm