Can you spot it? If so, leave your answer in the comments! Once someone has guessed it correctly, I'll blog again about this new feature, and other things coming in 4.4, in greater detail.
(Oh, and if you hang out in #plasma on irc or are a member of the Plasma team, please don't give the answer away. :)
This feature is also a neat example of how we work together in Plasma, building on top of what each other does, filling in the blanks when someone else gets stuck and riffing on each other's ideas. This particular feature was built on top of some work done in 4.2 by Jason Stubbs; the feature itself was started by Sebastian Kugler and finished by Marco Martin using some hints from a similar feature I fixed up for 4.3 in the system monitor widget, which in turn was written primarily by Petri Damsten.
(... and yes, I know, 4.3 isn't even out yet and we're already teasing you with new things ;)