AdGuard releases Manifest V3 compatible ad blocker for Chrome
AdGuard, the company best known for its content blocking solution, has released what it calls the “world’s first ad blocker based on Manifest V3”.
Chrome and Chromium-based browser users who haven’t been following the news regarding the future of extensions in browsers, may need a quick explanation to better understand what’s to come in the months and years. coming.
Google announced plans to release a new extension manifesto in 2018. The V3 manifesto defines what extensions can and cannot do in the Chrome web browser and any other browser that implements it. Extension developers, privacy advocates, and users criticized Manifest V3 soon after. The developer of uBlock Origin, which runs one of the most respected content blockers, said the release of Manifest V3 could mean the end of uBlock Origin for Chrome.
Some browser makers, including Mozilla, maker of Firefox, have openly stated that they will not implement Manifest V3’s limiting changes. Google made some concessions, but went ahead with the launch of Manifest V3 in the company’s Chrome web browser.
As of January 2023, extension developers will no longer be able to release new Manifest V2 extensions or update existing ones. Starting June 2023, Manifest V2 extensions will no longer work in Chrome.
In other words: extension developers must update their extensions to be compatible with the new Manifest V3 or end development for Chrome. Some Chromium-based browsers may change the default behavior to support Manifest V2 extensions, but most probably won’t.
AdGuard MV3 browser extension
AdGuard has released a new browser extension for Chrome and other Chromium-based browsers, based on Manifest V3. AdGuard users do not need the extension, as the core solution runs system-wide.
Extension work began in mid-2021. The developers note that the new APIs in Manifest V3 caused a lot of headaches during development. Although they managed to produce a working content blocker based on Manifest V3, they admit that it has some limitations that Manifest V2 content blockers did not have.
One of the major issues with Manifest V3 is that it imposes a hard limit of 330,000 rules for all extensions installed in Chrome. Each extension has guaranteed access to 30,000 rules. The number may seem like a lot, but when you realize that modern content blockers rely on tens of thousands or even hundreds of thousands of rules, the limitation becomes immediately apparent.
Take uBlock Origin as an example. uBlock Origin’s default configuration uses 80435 network filters and 45243 cosmetic filters; this is already more than four times the guaranteed minimum limit of the rules. Users can add their own custom rules to many content blockers or subscribe to more rule lists. It’s easy to hit the 330,000 rule limit with a single extension.
Now imagine that other extensions are installed and based on rules. These then compete with each other regarding limits.
Dynamic rules have an even tighter limit of 5,000, which includes a limit of 1,000 regular expression rules. When the limit is exceeded, only the first 5000 rules will be applied by the content blocker, while all other rules have no effect.
The AdGuard MV3 browser takes this into account. The developers have added warnings to the extension that notify users when rule throttling forces the extension to reduce the number of rules it supports. In fact, the developers note that even the basic filter lists, which are AdGuard’s main list, can be disabled in the worst case, since they contain more than 30,000 rules. For users, this may mean that the installed content blocker does nothing at all.
AdGuard’s new browser extension for Chrome demonstrates that content blockers are possible under Manifest V3. Compared to Manifest V2 content blockers, Manifest V3 extensions may be less powerful due to the artificial limits of Manifest V3 rules. In particular, the concurrent part is troublesome, as extensions can stop working if rule limits are reached.
Most Chrome users may want to switch to another browser when Manifest V3 becomes the norm to get reliable, non-chaotic protection.
Now you: are you affected by Manifest V3?