Rui Carmo
An anonymous tipster passed this on to me after I had pretty much given up on figuring out how some third-party keyboards managed to sport dedicated Home and Spotlight keys.
I still don’t know exactly how they do it, or why Apple doesn’t expose the basic app switching functionality as, say, the Mission Control key on their own Bluetooth keyboard, but at least now I have a mostly usable way to navigate the entirety of the UI (at least on properly designed apps), as long as I remember to use Ctrl Alt S to silence VoiceOver and to “press” items with both arrow keys.