Comment by virtujoel

Even "newly available" doesn't seem correct. For example:

https://modern-css.com/smooth-height-auto-animations-without... This claims `interpolate-size` is newly available and works in all major browsers.

https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/P... This states `interpolate-size` only works in Chrome/Edge.

I tested the demo and it's definitely not working in my copy of Firefox.