A rather bold easter egg trigger would be to just use the PS logo on the top app bar in the Magic Folder browser (= main screen), but that probably confuses people quite a bit?
Another idea I have is adding a "global" menu on the right of the main screen (the Magic Folder browser's top app bar).
Could be a burger, three dots, a gearwheel or so.
Clicking that, in lieau of a settings menu, could for now just call the tech demo screen.