It's not actually "hidden", it's simply extremely difficult to see, at least in the default "skin". I think it is white and the color of the box it's in is a very light, blue-grey.
Plus, for some reason, the top ~100 pixels of the window is not normally visible; the window automatically scrolls up by about that much. That's my fault!
The link I had on my personal home page had a few extra characters at the end of the url, "...index.php
#c2" That takes one to the "c2" anchor which is the start of the "WeatherCat" section, just below the "News" part.
Sekond misteak ov thee yeer! It reelie shud kount az thee last won four MMXV...
It simply isn't easy to see/detect/determine what it's for. In my humble opinion it's a poor design:
1. Very small, unlabeled, non-intuitive symbol
2. Color choice very, very close to surrounding colors, very little contrast
3. Nothing in the Help/explanation from SMF.