Chrome’s new adblock-limiting extension plan is still on. The company paused the rollout of the new “Manifest V3” extension format a year ago after an outcry over how much it would damage some of Chrome’s most popular extensions. A year later, Google is re-starting the phase-out schedule, and while it has changed some things, Chrome will eventually be home to inferior filtering extensions.
Google’s blog post says the plan to kill Manifest V2, the current format for Chrome extensions, is back on starting June 2024. On that date (we’ll be on “Chrome 127” by then) Google will turn off Manifest V2 for the pre-stable versions of Chrome—that’s the Beta, Dev, and Canary channels. Google says “Manifest V2 extensions [will be] automatically disabled in their browser and will no longer be able to install Manifest V2 extensions from the Chrome Web Store.”
The timeline around a stable channel rollout is worded kind of strangely. The company says: “We expect it will take at least a month to observe and stabilize the changes in pre-stable before expanding the rollout to stable channel Chrome, where it will also gradually roll out over time. The exact timing may vary depending on the data collected, and during this time, we will keep you informed about our progress.” It’s not clear what “data” Google is concerned with. It’s not the end of the world if an extension crashes—it turns off and stops working until the user reboots the extension. Maybe the company is concerned about how many people Google “Firefox” once their ad-blocker stops working.
Enterprise users with the “ExtensionManifestV2Availability” policy turned on will get an extra year of Manifest V2 compatibility.
Google’s sales pitch for Manifest V3 is that, by limiting extensions, the browser can be lighter on resources, and Google can protect your privacy from extension developers. With more limited tools you’ll be more exposed to the rest of the Internet, though, and a big part of the privacy-invasive Internet is Google. The Electronic Frontier Foundation called Google’s description of Manifest V3 “Deceitful and Threatening” and said that it’s “doubtful Mv3 will do much for security.”
Firefox’s Add-On Operations Manager also didn’t agree with any claims of privacy benefits, saying that, while malicious add-ons “are mostly interested in grabbing bad data, they can still do that with the current webRequest API.” In a later article the EFF also points out that Google’s “lighter on resources” argument also doesn’t really hold water. Anyone can open the Chrome Task Manager and see that a single website can take up a huge amount of memory, often in the 200MB+ range. On the high end now for me, Slack is drinking 500MB, while a single Google Chat tab, created by this company that is so concerned about performance, is at 1.5GB of memory usage. Something like uBlock Origin, across all your tabs, is in the 80MB range.
The one part of Manifest V3 that everyone can agree on is that it will hurt ad blockers. Google is adding a completely arbitrary limit on how many “rules” content filtering add-ons can include, which are needed to keep up with the nearly infinite ad-serving sites that are out there (by the way, Ars Technica subscriptions give you an ad-free reading experience and make a great holiday gift!). Google originally went with a completely crippling limit of 5,000 rules, and after the widespread outrage during its first attempt to push Manifest V3, the company upgraded filtering to a “more generous” limit of 30,000 rules. uBlock Origin comes with about 300,000+ filtering rules you can enable, and you can also import additional blocking lists and have that number skyrocket.
As far as we can tell, there’s no justification at all for arbitrarily limiting the list of filter rules. Manifest V2 does not have a limit and works great. Firefox is also implementing Manifest V3—it basically has to because Chrome is so much more popular—but it’s doing so without limits to filtering and other capabilities. Mozilla’s blog post on the subject promises “Firefox’s implementation of Manifest V3 ensures users can access the most effective privacy tools available like uBlock Origin and other content-blocking and privacy-preserving extensions.”
Once Manifest V3 happens, Chrome users will be limited to “uBlock Origin Lite,” while users will need to switch to Firefox or some other non-limited browser to get the full extension. An FAQ on the project details just how many feature regressions there will be—in addition to the hard limits on filtering rule sets, there are a host of other limits on filtering now. Items can’t be filtered based on the response headers or according to the URL in the address bar. Developers are more limited in what regular expressions they can use, along with a host of other technical limitations.