Interesting news for Matter!
Google is holding the second Smart Home Developer Summit on October 21st. And the Matter protocol is very prominent, spanning the biggest part of the event with 3 presentations (Although - the whole event is only 2 hours 15 minutes long, so don’t get over excited 
).
I’m looking forward to it and pay close attention of course!
I see the Matter updates will be to their WIFI nest hubs and latest thermostats. Not their fire alarms. I was hoping to make use of their motion sensing
Matter will support only a limited number of device types initially (like bulbs, switches etc.). I can’t think of a place where the types are listed. It was probably said in a podcast or so that supported types will grow over time.