Rules with :where() pseudo class are rejected

[AdamWr]

Steps to reproduce

1. Add this rule:

example.org##div > :where(h1, p)

https://developer.mozilla.org/en-US/docs/Web/CSS/:where

2. Go to - https://example.org/

div > h1 and div > p should be hidden, but rule is rejected.

cssfilter: cssfilter_addrule(): Rule is not valid, ignoring it (example.org##div > :where(h1, p))
AGProxyFilter: Rule rejected by all filters: example.org##div > :where(h1, p)

Screenshot

[ameshkov]

@AdamWr is it okay in the browser extension?

[AdamWr]

No, it isn't.
Created issue here - AdguardTeam/AdguardBrowserExtension#1998