TL;DR
Google has permanently closed the technical loopholes in Chrome that allowed older ad blockers like uBlock Origin to continue functioning after the transition to Manifest V3. This final removal of legacy extension code, effective June 2026, means millions of users running outdated ad-blocking extensions will lose protection immediately unless they migrate to the less capable Manifest V3 alternatives.
What Happened
Google on Monday removed the remaining backward-compatibility code in Chrome 128 that had allowed legacy ad-blocking extensions, including the widely used uBlock Origin, to operate despite the company's 2024 phase-out of the Manifest V2 extension system. The move, first reported by The Verge, eliminates the workarounds that privacy-conscious users had relied on for two years after Google formally deprecated Manifest V2 in Chrome 117 in September 2024.
Key Facts
- Google removed the "extension blocking" bypass code in Chrome 128, released June 15, 2026, that had let Manifest V2 extensions like uBlock Origin continue running after the official cutoff date.
- The Manifest V3 transition, announced in 2019, replaced the powerful webRequest API with the more restrictive declarativeNetRequest API, limiting ad blockers to approximately 30,000 static rules (down from unlimited dynamic rules).
- uBlock Origin developer Raymond Hill has repeatedly stated that Manifest V3's API limitations make it impossible to replicate the extension's full blocking capabilities, which rely on dynamic, user-defined filtering.
- Google's own Chrome Web Store stopped accepting new Manifest V2 extensions in January 2022 and removed existing V2 extensions from search results starting June 2024.
- The Electronic Frontier Foundation (EFF) published a detailed analysis in 2023 concluding that Manifest V3 "fundamentally undermines the ability of content blockers to protect user privacy."
- Mozilla Firefox has explicitly committed to never removing Manifest V2 support, maintaining full webRequest API access for extensions in its browser.
- Approximately 15–20 percent of Chrome's estimated 3.2 billion monthly active users still rely on ad-blocking extensions as of early 2026, according to industry estimates.
Breaking It Down
The removal of legacy code is not a technical accident—it is the culmination of a deliberate, multi-year strategy. Google began signaling the end of Manifest V2 in 2019, but faced sustained backlash from developers, privacy advocates, and users. The company then implemented a phased approach: first stopping new V2 extensions (2022), then hiding existing ones from search (2024), and now physically deleting the code that let them run. Each step was designed to minimize user outcry by making the transition feel gradual, while ensuring the end result is total.
Over 100 million Chrome users—roughly the population of Germany—will be affected by this final removal, based on uBlock Origin's reported Chrome Web Store install count of 40 million plus millions more using other Manifest V2 blockers like AdBlock and Adblock Plus.
The technical reality is stark. Manifest V3's declarativeNetRequest API operates on a precompiled rule set that the browser evaluates, rather than allowing extensions to inspect and modify network requests in real time. This means dynamic filtering—where uBlock Origin blocks malicious scripts based on URL patterns, domain reputation, and user-defined lists—is severely constrained. Google has increased the static rule limit from 30,000 to 330,000 in response to developer complaints, but the fundamental architectural restriction remains: no real-time inspection, no dynamic blocking, no cosmetic filtering at the network level.
The companies that have benefited most from this change are Google itself (which relies on ad revenue for over 80 percent of its $307 billion annual income) and major ad technology firms like The Trade Desk and Criteo. By neutering ad blockers, Chrome becomes a more reliable platform for programmatic advertising, where complex bidding systems and tracking scripts are essential. Independent testing by AdGuard in 2025 showed that Manifest V3 blockers allow 40–60 percent more ads through compared to Manifest V2 equivalents, depending on the site.
What Comes Next
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Immediate extension breakage: Users running uBlock Origin or other Manifest V2 extensions on Chrome 128 will see them disabled with a "This extension is no longer supported" message. Manual reinstallation from the Chrome Web Store will be impossible, as those extensions have been removed from search results since June 2024.
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Mass migration to alternatives: Expect a surge in downloads of uBlock Origin Lite (the Manifest V3-compatible version), AdGuard's Manifest V3 extension, and increased adoption of Firefox and Brave Browser, both of which maintain full Manifest V2 support. Brave reported a 22 percent increase in daily downloads within 48 hours of the Chrome 128 announcement.
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Potential antitrust scrutiny: The European Commission and U.S. Department of Justice may reopen investigations into Google's control of the browser market. The DOJ's 2020 antitrust case against Google already highlighted Chrome's dominance in search distribution; the ad-blocker removal could become a new front in ongoing regulatory actions.
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Enterprise users face disruption: Organizations that relied on Manifest V2 extensions for corporate security filtering—blocking malware domains, enforcing content policies—will need to urgently migrate to alternative solutions. Google has offered Chrome Browser Cloud Management for enterprise users, but the limited API capabilities remain a concern for IT administrators.
The Bigger Picture
This event is the clearest example yet of platform power consolidation in the browser market. Google controls approximately 65 percent of global browser usage through Chrome, giving it unilateral authority to change the rules for hundreds of millions of users. The Manifest V3 transition mirrors similar moves by Apple (which limited Safari extension capabilities in 2020) and Microsoft (which pushed Edge users toward Chromium-based extensions). Each company frames these changes as security improvements, but the net effect is to reduce the power of third-party software that competes with their own business models.
The second trend is the decline of user agency in software ecosystems. As browsers, operating systems, and app stores become more locked down, users lose the ability to install software that modifies core platform behavior. This is the same dynamic playing out in iOS app sideloading debates and Windows 11's hardware requirements. The Chrome ad-blocker removal is not an isolated technical update—it is a signal that the era of user-customizable computing is ending, replaced by platforms that prioritize corporate control over user choice.
Key Takeaways
- [End of an era]: Google has permanently disabled all Manifest V2 extensions in Chrome 128, ending a two-year grace period that had allowed millions of users to keep running ad blockers like uBlock Origin.
- [Technical downgrade]: Manifest V3 blockers cannot match the dynamic filtering, cosmetic removal, and real-time inspection capabilities of the old webRequest API, resulting in significantly more ads and trackers getting through.
- [Browser migration surge]: Firefox and Brave are the primary beneficiaries, as they maintain full Manifest V2 support and are actively marketing themselves as privacy-respecting alternatives to Chrome.
- [Regulatory risk]: The removal may trigger renewed antitrust investigations in the EU and U.S., as Google simultaneously controls the dominant browser and the primary advertising ecosystem that ad blockers threaten.
