This actually shows me some interesting technical info. Let me give a brief history lesson to explain.
There is a Linux desktop environment called KDE. KDE developed its own "widget toolkit" (library code for producing common programming widgets like buttons, scroll bars, tabbed dialogs, yes/no prompts, etc) many years ago called QT (pronounced as "cute"). KDE has always included a browser called Konqueror (all their app names have a K prominent in them). When Apple decided to make Safari, they decided instead of starting with an HTML rendering engine from scratch they would search for and improve an existing system. They chose KHTML, the library behind the HTML rendering in Konqueror. They improved and extended this library and re-released it as WebKit.
WebKit is now the rendering engine behind Chrome and Safari. The most recent versions have the best support for HTML5. It can easily be tied to the v8 JavaScript engine to support complex applications, and I believe this is probably already done in the car's browser if it supports gmail. WebKit has bindings for several languages and widget sets like QT, GTK (another Linux toolkit), Windows and Quartz (the Mac OSX toolkit). Seeing that it uses QtWebKit tells me that the entire UI in the Model S is probably QT-based. That also indicates that it's probably largely written in C++. The graphical parts, not necessarily the underlying system.
I also see from this output that the screen resolution is 1920x1200 (huge!), and that the processor is an ARM 7. I've read somewhere that it's an nVidia Tegra 3 specifically, but I don't remember where I saw that.
This doesn't really change anything I think about the car, it's just cool information to me