Each line of this definition tells HotkeyNet one of the four pieces of information that it needs for a hotkey.
1. The keys that you press to trigger the action. In this case, Ctrl F3.
2. The computer on which HotkeyNet types text or takes some other action. In this case it's the local computer, which means the computer on which you pressed Ctrl F3.
3. The window that the text appears in. In this case it's the window of a program called Ubertastic.
4. The action to be taken. In this case, HotkeyNet types "Whoopee!"