Since recently (I cannot say exactly but probably since KF 5.25) previously added (D2361) service menus stopped supplying 'Extract' and 'Compress' submenus. Instead, these submenus are now provided as standalone plugins. So I'm proposing to start adding plugin actions as well. I've basically copied the required code from dolphin/src/dolphincontextmenu.cpp.
Is this the way we want to go? The downside of this approach is that we don't supply a configuration interface for visibility of these plugins. It is now configurable by dolphin Settings only. Personally I find it quite ok but I'd like to hear your opinions.