Firefox found a way to keep ad-blockers working with Manifest V3

[harlan4096]

Firefox found a way to keep ad-blockers working with Manifest V3​

In a Tuesday blog post explaining the new extensions system, Mozilla says it adopted Manifest Version 3 to make things a lot easier for people developing extensions for both Chrome and Firefox. But while its implementation is largely meant to be cross-compatible, the organization says its version is different from Google’s in “some critical areas,” mainly security and privacy.

Google also cited those areas when it added Manifest V3 to Chrome in 2021, calling the move “part of a shift in the philosophy behind user security and privacy.” But one of the changes in the update broke features in several popular content and ad-blocking extensions by removing a feature they used to block certain network requests (be those to trackers, advertisers, or anyone else).

I won’t go too deep into how it did that — we have an explainer that goes into the technical side of things — but the high-level takeaway is that Mozilla’s version of Manifest V3 keeps the feature Google removed, while adding support for the more limited replacement as well. That should make it so content-blocker developers don’t have to create new (and potentially more limited) versions of their extensions, while making it easier for other developers to write multi-platform extensions.

I won’t go too deep into how it did that — we have an explainer that goes into the technical side of things — but the high-level takeaway is that Mozilla’s version of Manifest V3 keeps the feature Google removed, while adding support for the more limited replacement as well. That should make it so content-blocker developers don’t have to create new (and potentially more limited) versions of their extensions, while making it easier for other developers to write multi-platform extensions.

There are downsides to this approach; Mozilla itself admitted last year that there can be security risks to leaving that feature in. Apparently the foundation believes it’s worth the risk to preserve content blocking, which it called “one of the most important use cases for extensions.”

Here’s what’s going on in the world of extensions