You can read about it at AppleInsider or also the Thunderbolt experts at OWC.
I love that it will continue using the USB C port, but the fact that it allows so much more power scares me as it means hubs will be even more expensive, and I use so little in powered from the ports. I would love the speed though, and even better for video, so you could get better resolution at higher frame rates.
And you know this will show up in an Apple product first, maybe the next Mac Studio? That would make sense to me.