As to “key focus” - I think they actually mean “one-key focus”.
See modes:
Spotlight high – spotlight low – floodlight high – floodlight low – flash

So you use “one key” (tail switch) to both adjust “focus” and switch output level.
I think that it has 2 separate optics, one is floody (spotlight) and the other is floodier (floodlight). As you switch modes the light switches between them.

Which seems like a terrible UI really. If I want to switch mode I don’t want to have to cycle through entirely different beam shape and through strobe. :person_facepalming: