New Chrome extension rules could hobble ad blockers

Google Chrome update
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Update (10/03/2022): Google has unveiled its roadmap for Manifest V3's rollout. As detailed in a blog post, Google may start turning off support for Manifest V2 extensions in Canary, Dev and Beta channels with Chrome 112. Then in June with Chrome 115, the company will start turning off support for Manifest V2 extensions in all channels, including the stable channel.

Original story (10/01/2021): Google announced this week that Chrome browser extensions written to conform only with its outgoing Manifest V2 specification may no longer function come January 2023. 

Afterward, Chrome will support only extensions that conform to the Manifest V3 rules — and that could mean the end of some ad blockers and privacy extensions.

"Years in the making, Manifest V3 is more secure, performant, and privacy-preserving than its predecessor," product manager for Chrome extensions and the Chrome Web Store David Li said in a blog post. "It is an evolution of the extension platform that takes into consideration both the changing web landscape and the future of browser extensions."

Li said new Manifest V2 extensions will not be accepted by the Chrome Web Store after Jan. 17, 2022, three and a half months from now. Developers can still release updates to existing Manifest V2 extensions. 

Sometime in January 2023, Chrome will no longer run Manifest V2 extensions at all. Li said Google will share more details as these dates draw closer. There's a more detailed timeline posted here.

More secure...

Google says the revision of the Chrome browser extension framework will address security issues, a claim it made when Manifest V3 was first introduced in 2019. 

That's certainly a legitimate concern, as malicious browser extensions have been running rampant in the Chrome Web Store in the past few years, although Google seems to have been doing a better job of policing extensions during 2021. Many of the extensions abused the powers they held under Manifest V2 to spy on users and steal sensitive information.

Some experts, however, aren’t convinced that this is about user security or privacy. 

"Our criticism still stands," said Alexei Miagkov, senior staff technologist at the Electronic Frontier Foundation, to The Register. "The reasons they have stated publicly [for this transition] don't fully make sense."

In 2019, Miagkov was co-author of an EFF report that said "Manifest V3 is a blunt instrument that will do little to improve security while severely limiting future innovation."

One widely used browser extension that likely won't work under Manifest V3 is the EFF's own Privacy Badger, which blocks web trackers.

... or more ad-friendly?

An annual report that Google filed in early 2019 with the U.S. Securities and Exchange Commission (SEC) stated that ad-blocking technology could affect Google’s revenue. Google also pays Adblock Plus to whitelist its online advertising, and Adblock Plus appears to conform to Manifest V3. 

Around the same time, Raymond Hill, who maintains the free uBlock Origin and uMatrix ad blockers, posted in a Chromium developers' forum that Manifest V3 meant that his two ad blockers could "no longer exist." (Chromium is the open-source platform on which Chrome and many other browsers are built.)

Along with Hill, other suspicious minds wonder whether nuking ad blockers could be the real reason for the Manifest V3 overhaul of browser extension permissions. 

Yet Simeon Vincent, a developer advocate for Chrome Extensions, said in later in 2019 that Manifest V3 would not disable ad blockers but would instead let developers make better ad-blockers.

It's not clear how much money Google and publishers lose because of ad blockers, but the company’s claim that Manifest V3 will help developers create better ad blockers seems somewhat unlikely.

An opportunity for rival browsers?

It will be interesting to see what happens when and if many ad blockers and privacy extensions cease to function on Google Chrome, but rival browsers continue to support them.

Firefox maker Mozilla says it will support Manifest V3 but also let ad blockers work; Microsoft has implied it will do the same in Edge. Brave, like Edge, is Chromium-based but says it blocks ads (by default) at a deep level that won't be affected by Manifest V3. 

Chrome currently has about two-thirds of the global desktop browser market, according to StatCounter. The rest are all below the 10% mark. If Chrome gets rid of ad blockers and the others don't, it could be a chance for them to reclaim a bigger piece of the pie.

Tony Polanco
Computing Writer

Tony is a computing writer at Tom’s Guide covering laptops, tablets, Windows, and iOS. During his off-hours, Tony enjoys reading comic books, playing video games, reading speculative fiction novels, and spending too much time on X/Twitter. His non-nerdy pursuits involve attending Hard Rock/Heavy Metal concerts and going to NYC bars with friends and colleagues. His work has appeared in publications such as Laptop Mag, PC Mag, and various independent gaming sites.