Why is there a filter limit at all? Why did Firefox add that? Can config change it?

Filters aren't free

They are quite often better than free, blocking unwanted content that would consume more memory and CPU time than the filter itself.

Filters take a minuscule amount of resources. E.g. Even if you had to loop over a list with thousands of entries this would be unlikely to matter, and can in fact even be optimized quite significantly with various algorithms. However, because a database is most likely used, this is not even an issue, and the resource use will in fact be truly minimal.

I can not give you an exact number, but it is massively bigger than the number of trackers / elements that any usable web page can realistically implement. Probably you can do several thousands database calls in less than a second due to indexing; and that can be further optimized by doing it in batches, bringing it up to tens of thousands, if not in the hundreds on modern PCs. It is literally not an issue.

Is the limit still around 30,000 or is it higher? That could be 600,000 filter checks on a page load with 20 requests.

I'm sure it's fast but if people want unlimited number of rules that number could start exploding.

> Why did Firefox add that?

They didn't, Google did. It is part of MV3 specs, afaik.

But Firefox still didn't have to implement the limit.

Then don't use the downgraded version of the ad blocker? What is the point of having two versions of MV3 when you can use a superior adblocker on Firefox anyway?

Google doesn't make Firefox. I flatly don't understand why Mozilla has that limit.