Google’s latest crackdown on browser extensions has rendered popular ad blockers like uBlock Origin inoperable on Chrome, as the company pushes forward with its transition to Manifest V3.
The shift, which has drawn criticism for weakening privacy protections, impacts all Chromium-based browsers, including Microsoft Edge. Meanwhile, Firefox has reinforced its commitment to ad-blocking tools, pledging to support both Manifest V2 and V3 to ensure users retain control over their browsing experience.
Manifest V3, the latest iteration of Chrome’s extension framework, has faced scrutiny for restricting access to key functionalities used by ad blockers. It serves as the foundation for WebExtensions, which power browser APIs. Google has defended the move, calling it “the first step in our platform vision to improve the privacy, security, and performance of extensions.”
Previously, uBlock Origin operated on Manifest V2 using a feature known as blockingWebRequest. Chrome has now replaced this with declarativeNetRequest, which limits how extensions interact with web content. Google initially announced plans to phase out support for Manifest V2 extensions in late 2023, with a series of updates in early 2025 further disabling tools like uBlock Origin.
In contrast, Mozilla has reaffirmed that its Firefox browser will continue supporting both blockingWebRequest and declarativeNetRequest. Although Firefox holds a modest 3.7% share of the browser market, its dedicated user base values privacy and customization. In addition to robust built-in ad blocking, Firefox continues to support third-party extensions like uBlock Origin.
Mozilla’s stance reflects its broader philosophy of user empowerment. “More tools for developers means more choice and innovation for users,” wrote key figures from the Firefox add-ons team. “Giving people choice and control on the internet has always been core to Mozilla. It’s all about making sure users have the freedom to shape their own experiences online.”
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