https://www.cnet.com/news/the-future-of-googles-smart-home-starts-with-a-button/

The buttons are powered by software called Google Assistant Connect. Google showed off prototypes of the buttons and first debuted Connect back at CES in January. Now, it's showing off a developer kit for Connect and the button is real. Google Assistant Connect, along with another kit called "Local Home," look to make a Google-powered smart home faster and more versatile.

Google Assistant Connect is a low-cost way of making a device compatible with Google Assistant -- the company's voice activated digital helper similar to Amazon's Alexa. It's a kit that functions as a reference design for developers. Make a device with Google Assistant Connect, and Google takes care of the computing so the developer can focus on making creative hardware.