/usr/share/gnome/help/glade-gtk2/en_GB/figures/main-window.png is in glade-gtk2 3.8.0-0ubuntu4.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/gnome/help/glade-gtk2/en_GB/figures/../../C/figures/main-window.png