Google postpones Chrome changes that could have big impact on ad blocking extensions

It is no longer planning to begin turning off the old extensions standard in January and says the rest of the timeline is ‘under review.’

Google no longer plans to begin turning off the Chrome browser’s old extensions standard in January, the company’s developer advocate for Chrome Extensions, Simeon Vincent, has announced (via 9to5Google). The company is currently in the process of transitioning from the Manifest V2 (MV2) extension standard to Manifest V3 (MV3), which Google says will improve the security and performance of its browser. Critics, however, have claimed MV3 will make it harder for ad-blocking extensions to work.

My former colleague Corin Faife wrote an excellent explainer on the controversy earlier this year. But the TL;DR is that MV3 swaps out a powerful API used by ad-blocking extensions called Web Request for another called Declarative Net Request. The latter gives less power to ad-blocking extensions in an attempt to minimize security risks, but critics argue it restricts actions legitimate extensions might take to protect user privacy. Corin’s piece is well worth reading for a more thorough explanation.

As of late September, Google had planned to experiment with turning off MV2 in Chrome’s Canary, Dev, and Beta channels starting in January 2023, broaden the experiments to include the browser’s stable releases in June 2023, and stop running MV2 extensions entirely in January 2024. But as of December 9th, it’s postponing the January experiments and placing future milestones “under review.”

In his post, Vincent says the timeline has been pushed back to address feedback from developers. “We’ve heard your feedback on common challenges posed by the migration, specifically the service worker’s inability to use DOM capabilities and the current hard limit on extension service worker lifetimes,” he writes. “We’re mitigating the former with the Offscreen Documents API (added in Chrome 109) and are actively pursuing a solution to the latter.”

While rival privacy-focused extension Ghostery has opposed the MV3 changes, it’s worth noting they have the support of Adblock Plus. But ad-blocking is a sensitive topic when it comes to Google, given advertising still provides so much of the company’s income. And since the changes are being made to the Chromium project and not just Chrome specifically, they’re likely to impact other browsers like Edge, Brave, and Opera.

Despite the delays, it sounds like Google doesn’t have any plans to ditch its migration to MV3 entirely. Vincent says that Google will announce an “updated phase-out plan and schedule” in March next year.