Yeah, okay. So: Clearing Browser cache is a common feature in any webbrowser (even Chrome, and if Chrome has it, everyone has)
Regarding insights into the local cache: Are you technically versed enough to understand what you are seeing? If not, what good would looking at the cache do to you? I mean, whatever is in that cache is no indication about your privacy at all. As @minitycactus found out, Wikipedia logs your last visit. Do they spy on you? Very probably not. Besides, whatever they put into local cache is not something they have on their servers,
I wouldn't put too much energy into a search for that specific feature.