Šime Vidas with the lowdown on what these pseudo-selectors are and why they will be useful:
:is()
is to reduce repetition¹ of parts of comma-separated selectors.:where()
is the same, but nothing inside it affects specificity. The example of wrapping:where(:not())
is really great, as now there is a way to use:not()
without bumping up the selector weight in a way you very likely don’t want.
- This is something that CSS preprocessors are good at (via nesting). Another nice little example of community-built tech pushing forward and native tech coming up later to help once the idea is fleshed out.