Ad blockers face hurdle as Google Chrome starts rolling out Manifest V3

Manifest V3 cuts off access to remotely hosted code, a feature used by some ad blockers

Google Chrome is rolling out Manifest V3, its latest extension specification, starting 3rd June on the Beta, Dev and Canary channels, which could impact how effectively ad blockers work in the Chrome browser.

Google cited the community's progress and feedback as justification for proceeding with the decision.

"We've always been clear that the goal of Manifest V3 is to protect existing functionality while improving the security, privacy, performance and trustworthiness of the extension ecosystem as a whole," the company said.

"We appreciate the collaboration and feedback from the community that has allowed us - and continues to allow us - to constantly improve the extensions platform."

Starting next week, those using Chrome's Beta versions will be greeted with warnings on their extension management page. These warnings signal the impending demise of Manifest V2 extensions, which will soon lose their "featured" status in the Chrome Web Store.

These extensions won't be disabled immediately, but Google plans to phase them out entirely in the coming months.

Users will be able to temporarily re-enable them, but this option will eventually disappear.

The full shift to Manifest V3 is expected by early 2025 for the stable version of Chrome.

Manifest is essentially an instruction manual for extensions, telling the browser everything from the extension's name and purpose to the permissions it needs and compatible browser versions.

While Google touts Manifest V3 as a security and performance booster, it also restricts extension capabilities, particularly for ad blockers. The new system limits how these extensions access user data and update their filtering rules.

Notably, Manifest V3 cuts off access to remotely hosted code, a feature used by some ad blockers.

Since announcing its plan to introduce Manifest V3, Google has faced criticism over its potential to cripple ad blockers.

The company has since attempted to appease developers by enabling user scripts and expanding the rule sets for ad blocking extensions within the "declarativeNetRequest" API. However, a major drawback is the inability for extensions to update their rulesets automatically.

Any updates would require a whole new extension version submitted to the Chrome Store, potentially facing a weeks-long security review.

Despite concerns, Google maintains that over 85% of actively maintained Chrome extensions have Manifest V3 versions available, including popular ad blockers.

uBlock Origin, a popular ad blocker, has already created a Manifest V3 compatible version called uBO Lite. But the developers warn that this version may require more user configuration and may not be as effective as the original.

Firefox, the primary competitor to Chrome, argues Manifest V3's limitations don't significantly hinder malicious extensions, which are more focused on data collection, something still possible under Manifest V3.

Firefox plans to support Manifest V3 to ensure extension compatibility with Chrome, but it will also continue supporting Manifest V2, providing developers and users with more flexibility.