/usr/share/icons/hicolor/128x128/apps/iceweasel.png is in iceweasel 38.8.0esr-1~deb7u1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/icons/hicolor/128x128/apps/../../../../iceweasel/browser/icons/mozicon128.png