Since the applets are dynamically loaded, the .desktop files don't need an X-KDE-Library entries, but the others will be used, for example X-KDE-PluginInfo-Name (which will be the value given to PluginLoader::internalAppletLoad, so it is really important), Icon, Type, ServiceTypes...
svn path=/trunk/KDE/kdelibs/; revision=1154551
plasma will query for Applet, DataEngine, and Service creation, giving them
the chance to create these objects internally.
http://reviewboard.kde.org/r/4554/
svn path=/trunk/KDE/kdelibs/; revision=1150389