This is great, thanks! As someone that has been working with css for over a decade, I was surprised to find out about the contain property, as I had never know

This is great, thanks! As someone that has been working with css for over a decade, I was surprised to find out about the contain property, as I had never known about it and it seems extremely useful for hinting to the browser of optimizing DOM operations. If anyone with experience writing DOM/layout code for browsers knows anything about whether these optimizations are indeed used/meaningful, that would be stellar!