Microsoft Edge has started warning users that the extension format behind the full version of uBlock Origin is on its way out. PCWorld reported this week that Edge is following Chrome toward Manifest V3 while Firefox keeps the capabilities the full blocker needs.
That sounds like the sort of browser maintenance only extension developers should care about. The money says otherwise. Alphabet collected $294.7 billion in advertising revenue in 2025, about 73 percent of its total revenue. The same company builds Chrome on Chromium and sets Chrome’s extension rules. Microsoft says Edge is built on the same underlying technology as Chrome, while Brave and Opera must decide how long to maintain their own exceptions. Google’s extension architecture reaches far beyond Chrome.
Google has a right to improve Chrome. It should not have enough control over the web to make its preferred limits the default limits for almost everybody else.
Most browsers now inherit Google’s decision
Google finished disabling Manifest V2 extensions in Chrome last year. Its deprecation timeline says the remaining Manifest V2 listings will disappear from the Chrome Web Store on August 31. Microsoft has now begun the same transition in Edge. Its current migration schedule says deprecation warnings began this month, with enterprise deprecation expected to start in early 2027.
The scale of that upstream decision is the story. StatCounter’s June 2026 desktop figures put Chrome at 72.24 percent, Edge at 10.45 percent, and Opera at 1.81 percent. Those three Chromium browsers alone account for more than 84 percent of the desktop page views StatCounter observed.
Google does not literally control every one of them. Brave and Opera can patch Chromium, ship native blockers, or preserve old extension support. That work costs engineering time forever. The upstream choice still sets the default, and every smaller browser must either follow it or maintain its own escape hatch.
Infrastructure monopolies rarely need a dramatic shutdown notice. One company changes an API, the dominant engine carries the change across the market, and user control survives only where a smaller vendor can afford to keep undoing it. The United Kingdom’s Competition and Markets Authority has already designated Google’s mobile browser and browser engine as having strategic market status. Different market, same warning: control of an engine becomes control of the choices built on top of it.
Manifest V3 changes who gets to decide
Manifest V2 gave extensions such as uBlock Origin a blocking version of the webRequest API. The extension could inspect a request as it happened and decide what to block, redirect, or modify based on the site, request type, initiator, and other context.
Chrome’s Manifest V3 design removes that blocking power from ordinary extensions. The replacement, declarativeNetRequest, asks extensions to hand rules to the browser in advance. Chrome then applies those rules itself.
That still permits real ad blocking. It also moves authority from the extension to the browser vendor. Chrome’s current API limits define how many rules can run, which kinds of dynamic rules count as safe, and which request actions are available. A future expansion or restriction arrives on Google’s schedule.
uBlock Origin Lite works inside those boundaries, and it is useful software. Its own developer says it is too different from the full uBlock Origin to be an automatic replacement. The Lite version gives up parts of uBlock Origin’s dynamic filtering, response manipulation, per-site controls, and independent filter update process. Users can still block a great deal. They lose some of the power to decide how.
Google did not kill every ad blocker. It made the browser the gatekeeper of acceptable blocking techniques, then exported that model through Chromium.
The security case is real and incomplete
Google and Microsoft have legitimate reasons for changing the extension system. Manifest V2 extensions with broad request access can see sensitive browsing data. Remotely hosted code makes review harder. Persistent background pages consume resources. Chrome says its declarative model can block requests without handing every URL and header to extension code, while also reducing per-request JavaScript work. Microsoft cites the same privacy, security, and performance goals.
Evidence also complicates the easy claim that Manifest V3 always blocks less. A 2026 study in Proceedings on Privacy Enhancing Technologies compared Manifest V2 and Manifest V3 versions of four blockers. It found no statistically significant decline in measured ad blocking and an average increase of about 1.8 blocked trackers per site in its Manifest V3 tests.
That finding deserves to be taken seriously. It measures common blocking outcomes, not the whole range of user controls. A predeclared rules engine can perform well against known advertising and tracking patterns while still lacking the full uBlock Origin toolset. Better guardrails for malicious extensions and durable support for powerful privacy tools can coexist. Mozilla proves the point by supporting Manifest V3 while retaining the blocking webRequest capability.
The security rationale also cannot erase the conflict of interest. Alphabet earns nearly three quarters of its revenue from advertising. It controls Chrome, whose extension rules Edge and other Chromium derivatives largely inherit. No public evidence proves that Google designed Manifest V3 to protect its ad business. The documented incentive conflict alone makes blind trust absurd.
Firefox is the exit ramp
Firefox is not literally the only browser where a determined user can keep blocking aggressively. Brave preserves several Manifest V2 extensions and has its own built-in Shields system. Opera says it will support existing Manifest V2 extensions for as long as it can. Those are valuable choices.
They remain choices made inside Google’s engine. Firefox is the last browser backed by a major independent engine with durable platform support for the capabilities that full uBlock Origin uses. Mozilla has committed to supporting Manifest V2 for the foreseeable future and retaining the blocking API in its own Manifest V3 implementation.
That independence is why Firefox’s 6.31 percent desktop share matters. Browser diversity gives users somewhere to go when the dominant engine vendor decides that an extension has too much power. It also gives standards bodies, developers, and smaller browser makers proof that Google’s implementation is one option rather than natural law.
The web should not require Google’s permission to resist Google’s business model. Every browser that simply inherits Chromium’s limits makes that permission harder to refuse. Firefox keeps an exit open, and the rest of us should understand exactly why we still need it.