[olpc-help] Where's the "view source" button?

[dpbsmith]

One of the most intriguing and potentially far-reaching features of the XO is the view source button (http://wiki.laptop.org/go/OLPC_Human_Interface_Guidelines/The_Laptop_Experience/View_Source).

The only problem is, I can't find it. It's not on the keyboard (http://laptop.org/en/laptop/start/keyboard.shtml). Is it only metaphorically a button, i.e. a visible part of the GUI? If so, it doesn't seem to be implemented in many Activities.

What's an example of an Activity that has a "view source" button, and whose source can be viewed?