My understanding is that security hub announced glass break detection from day 1. And that feature uses a microphone to listen to glass breaks... so I wasn't surprised. But, I guess that's not obvious to everyone, so they could've put it on the box.
And, I just didn't HN readers to think there was a mic on the thermostat, so I was correcting that.
Having a microphone to detect broken glass is very much not obvious. As someone completely unfamiliar with the problem space, I would have assumed the normal solsolution was something along the lines of: run a current throught the glass and check the voltage "drop".
I could see this if you connected the device to the system that monitored this. But since you never do that in the install process, I am not sure why you'd assume that's how the system would work.
It was in their security hub which is perhaps better or worse than the thermostat depending on your view.