I think that D3E key name list should define more keys which launches specific application like 'LaunchMail'.
GTK Qt Android Suggestions
GDK_Calculator Qt::Key_Calculator KEYCODE_CALCULATOR 'LaunchCalculator' as General
GDK_Memo Qt::Key_Memo 'LaunchMemo' as General
GDK_ToDoList Qt::Key_ToDoList 'LaunchToDoList' as General
GDK_Calendar Qt::Key_Calendar KEYCODE_CALENDAR 'LaunchCalendar' as General
GDK_ScreenSaver Qt::Key_ScreenSaver 'LaunchScreenSaver' as General
GDK_WWW Qt::Key_WWW 'LaunchWebBrowser' as General
GDK_MyComputer 'LaunchMyComputer' as General (?)
GDK_Shop Qt::Key_Shop 'LaunchShop' as Genral
GDK_History Qt::Key_History 'LaunchHistory' as General or 'BrowserHistory'?
GDK_Finance Qt::Key_Finance 'LaunchFinance' as General
GDK_Book Qt::Key_Book 'LaunchBookViewer' as General or 'Book' as Media
GDK_DOS Qt::Key_DOS 'LaunchDOSPrompt' as General (?)
GDK_Documents Qt::Key_Documents 'LaunchDocumentFolder' as General (?)
GDK_Excel Qt::Key_Excel 'LaunchSpreadSheet' as General (?)
GDK_Explorer Qt::Key_Explorer 'LaunchFileManager' as General
GDK_Game Qt::Key_Game 'LaunchGame' as General
GDK_Market Qt::Key_Market 'LaunchMarket' as General
GDK_Meeting Qt::Key_Meeting 'LaunchMeeting' as General
GDK_MySites Qt::Key_MySites 'LaunchMySites' as General
GDK_News Qt::Key_News 'LaunchNews' as General
GDK_OfficeHome Qt::Key_OfficeHome 'LaunchOfficeHome' as General
GDK_TaskPane Qt::Key_TaskPane 'LaunchTaskPane' as General
GDK_Terminal Qt::Key_Terminal 'LaunchTerminal' as General
GDK_Travel Qt::Key_Travel 'LaunchTravel' as General
GDK_Messenger Qt::Key_Messenger 'LaunchMessenger' as General
GDK_WebCam Qt::Key_WebCam 'LaunchWebCam' as General
GDK_Pictures Qt::Key_Pictures 'LaunchPicture' as General or 'Picture' as Media
GDK_Music Qt::Key_Music KEYCODE_MUSIC 'LaunchMusicPlayer' as General or 'Music' as Media
Qt::Key_LaunchMedia 'LaunchMediaPlayer' as General
Qt::Key_Community 'LaunchCommunity' as General?
Anyway, I think that we should confirm the key meaning which Android doesn't have to X11 expert.
FYI: I found this:
GDK Qt Suggestion
GDK_Word Qt::Key_Word 'LaunchWordProcessor'
We've added the following Launch Application keys. We can add more as needed, but many of the GDK and Qt names seem aspirational rather than keys that are found in the real-world.