Review of CSS containment

I reviewed CSS Containment Module Level 2 
<https://www.w3.org/TR/css-contain-2/> and CSS Containment Module Level 
3 <https://www.w3.org/TR/css-contain-3/>. We had previously reviewed the 
1.0 version and had no concerns.

Level 2 introduces the content-visibility property. The value 
content-visibility: hidden 
<https://www.w3.org/TR/css-contain-2/#using-cv-hidden> could replace CSS 
off-screen techniques, so we might want to suggest new techniques for 
WCAG. The section includes an accessibility implications section that 
describes how to represent the content in the accessibility tree. As far 
as I can tell, it provides the information needed to ensure this 
property is implemented in an accessible manner.

Level 3 adds naming for CSS containers, and expands on the types of size 
containment. As I understand it, it makes CSS layout more deterministic 
and fast. I do not see that it raises new accessibility-specific questions.

Therefore I think we can close the reviews of both versions with no 
comments.

Michael