[gkbrk]

> What is a static filter list other than a list of filters that does not change?

A request is being made. At the time of the request, you go through a list of rules and decide if you're going to block or allow it.

Once the request reaches the filter, you are working with a static list because you cannot make decisions using the content or circumstances of that particular request. You cannot add or remove anything to your list after looking at the request.

A dynamic filter on the other hand could

- Resolve hostnames with DNS to do CNAME uncloaking

- Decode encoded requests so the website cannot send both real data and analytics/tracking data through a single URL. Being able to make dynamic decisions allows the ad blocker to inspect request headers and request bodies.

- Modify responses. The web page could be getting ads from a JSON endpoint with the rest of the page. You can use filterResponseData and change the response dynamically to strip the ads return an empty JSON list for example.

[danShumway]

Exactly. Or in other words:

> It also reduces ad blockers to static filter lists instead of powerful dynamic filters. MV3 makes it impossible for ad-blockers to inspect requests with code and then allow/deny dynamically.

I'm assuming the best here, but it is extremely clear what you meant by a "static filter" in your comment. You meant a filter where it is "impossible for ad-blockers to inspect requests with code and then allow/deny dynamically."

It's a little frustrating to have to pretend that any of this is ambiguous.