This is a mistake on the part of the page authoring software, but this page contains this HTML: SautŽed Mushrooms In IE 5, this displays as a capital Z hacek, which is (presumably) the right character to be displayed (?). Instead we're displaying the square that signifies a non-existant character (?). (On the Mac, it displays some other character that I don't recognize.)

I changed it to be compatible with IE5, but this is a non-legal entity. Please don't ask for any more.

Right you are. I did a little bit of research and apparently early versions of IE and Microsoft Office used a bunch of illegal character numbers (from about 140 to 160, I can't remember exactly which ones) to represent things that at the time had no HTML equivalents (such as copyright and trademark symbols). Therefore, this is an invalid bug. Marking verified.