Google is removing the last technical workaround that kept effective ad blockers alive in Chrome.
When Chrome 150 ships on June 30, the browser will delete a hidden setting called the ExtensionManifestV2Disabled flag, a switch that power users had been toggling to keep old-style extensions running after Google officially discontinued them.
Without it, uBlock Origin and every other extension built on the old Manifest V2 framework, the set of rules that governed how browser extensions worked for years, will stop functioning permanently. Chrome 151, expected in July, will strip the remaining MV2 flags entirely. No policy override and no hidden setting will bring them back.
The company that sells more advertising than any other on Earth now controls whether you can block those ads. And it just decided you can’t, at least not effectively.
What Google took away and why it took it
The technical change is the replacement of Chrome’s webRequest API with the declarativeNetRequest API.
Under the old system, extensions like uBlock Origin could watch your browser’s traffic as it happened, see an ad or tracker trying to load, and block it on the spot before it ever reached your screen.
Under the new system, extensions have to hand Google a pre-written list of things to block and Chrome decides whether to follow those instructions. The lists are capped at a fixed number of rules, and the extension can’t react to anything that isn’t already on the list.
uBlock Origin’s developer, Raymond Hill, has been clear that a Manifest V3 version cannot replicate the original’s full capabilities. A stripped-down version called uBlock Origin Lite exists for MV3, but it handles only a fraction of the filter lists, the community-maintained databases of known ads and trackers, that the original supported.
It also can’t perform cosmetic filtering, the process of hiding ad containers and promotional elements that remain on a page even after the ad itself is blocked. Without it, you get blank boxes where ads used to be, or sponsored content that looks native to the page. For more than 40 million Chrome users who relied on the original, the replacement is a downgrade by design.
Google engineer Devlin Cronin confirmed the timeline in a Chromium code review commit, a logged change to Chrome’s underlying source code that other developers can inspect, writing that “MV2 extensions are no longer allowed in any supported version of Chrome, and we are removing support for them and the associated functionality. We won’t be able to provide / maintain this functionality indefinitely due to the complexity and tech debt, as well as the security risks it entails (we’ve actually found a number of bugs that are specific to MV2 lately). Of course, other browsers can continue supporting these if they so desire.”
Hellbound and Down 