In case you have not heard about Qt or your knowledge is a bit old, [the Qt White Paper is recommended](http://qt-project.org/wiki/QtWhitepaper This whitepaper describes the Qt C++ framework") for reading.
In order to have some functionality in the additional "TimeManager" class, it fetches the timezones in a Windows OS. For other OS types, you need to look further. In Qt 5.1 is expected to provide cross platform support for timezones.
The main C++ file puts together all the parts needed for an application.
The resource system Qt uses a XML file called
resources.qrc that lists all the files that are compiled in the resulting binary. In this case there is only the QML file.
The TimeManager class is defined in a header file (.h) and implemented in a C++ file (.cpp).
Please note that due to the Registery dependancy, this implementation only works in Windows.
QML file provides the User Interface.