I ran into what appears to be a logic issue in the web search filter list handling and am working on implementing a fix.

When a domain is added to the web search filter list with a ! prefix (block rule), search results from that domain should be excluded.

Currently, web search filtering resolves a result’s domain into:
the original domain (e.g. www.youtube.com)
multiple IPv4 / IPv6 addresses

If any one of those is not explicitly blocked, the result will not be blocked.

Would appreciate confirmation that this is unintended. Thanks!