June 30, 2026 is the day Google Chrome finally slams the door on Manifest V2 ad blockers. Chrome 150 removes the kExtensionManifestV2Disabled flag, the last practical loophole that let users keep uBlock Origin and similar extensions alive after the official Manifest V2 cutoff.
The Flag That Held the Door Open
Google began phasing out Manifest V2 in 2024, but a hidden flag -- kExtensionManifestV2Disabled -- remained in Chromium. Power users exploited it to re-enable blocked V2 extensions. A Google engineer just marked it as "dead code" in a Chromium commit, writing: "MV2 extensions are no longer allowed in any supported version of Chrome, and we are removing support for them and the associated functionality." The commit cites security bugs specific to MV2 and the accumulated tech debt of maintaining the backwards compatibility shim.
What Gets Removed and When
Chrome 150, landing at the end of this month, kills the primary workaround. A limited DevTools method will persist but requires manually patching page elements every session -- impractical for daily browsing. Chrome 151 in July finishes the job by stripping the remaining flags: ExtensionManifestV2Unsupported, ExtensionManifestV2Availability, and AllowLegacyMV2Extensions. The W3C WebExtensions Community Group documented the Chrome 150 removal on May 20, 2026, citing the same Chromium code review.
What This Means for Users
Popular ad blockers built on Manifest V2 -- uBlock Origin, AdBlock Plus legacy versions -- will stop working entirely for anyone on Chrome or Chromium-based browsers that follow Google's lead. Microsoft Edge and Opera are expected to adopt the same timeline. The Google engineer explicitly noted that other browsers can continue supporting MV2 if they choose, which leaves Firefox and Brave as the remaining refuges for users who refuse to switch to Manifest V3's more restrictive declarativeNetRequest API.
Chrome 150 ships in two weeks. If your ad blocker still works today, it won't after June 30.
Source: Google Chrome update will close the door on ad blockers
Domain: 9to5google.com
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