Oooh, Android S. What would it have been named? Snack? Sundae? Either way it's Android 12, and the developer preview has been out for a while for those app developers who want to make sure their app is going to work within the frame of it.
With Google I/O happening, they announced and showed off more of the Android 12 look and feel with the "Material You" design elements, etc...
and they also made the beta program available to a wider range of people - you visit https://android.com/beta and then opt in your phone.
I did it with my Pixel 4a (always just that extra bit cautious on my daily driver).
And definitely the elements are more 'bubbly' feeling. Bigger, more contrast that you can see in the control panel as you swipe down.
I haven't had much chance to play yet.
I'm getting a few errors with the launcher when I play around with different widgets (and not seeing all the widgets I think I should see).
I do like how it's feeling more fluid, and that in some cases when you touch an option, instead of just highlighting it there's like a 'sparkle' feature.