There's an old joke, something about a kid getting a drumset for christmas and dad giving the kid a knife and saying "ever wonder whats inside your new drumset?".
Well, you must be dying to know whats in your new Ecobee Switch+. And I can't believe I forgot to add it to the previous post. mea culpa what you must be thinking of me, you thought I installed it w/o disassembling it?
Looks like its an Atheros WiFi (but not soc?), and a Freescale i.MX28. Looks like a motion/light sensor, speaker driver, and below is power-supply + relay logic.