Chrome rips out final MV2 lifelines, ending uBlock Origin workarounds

Google has begun deleting the last code paths that kept Manifest V2 extensions alive in Chrome, closing every remaining loophole users relied on to run uBlock Origin. According to Chrome engineer Devlin Cronin, the kExtensionManifestV2Disabled feature flag — default-enabled for over a year — has been removed entirely from Chromium, along with the now-unreachable test code. Related enterprise and registry-based escape hatches are being stripped out across Chromium 150 and 151, including the Windows Registry tweak that let users extend MV2 support, which stops working after version 151.

Google’s stated rationale is maintenance burden and security: Cronin said the team can’t sustain the legacy functionality indefinitely given accumulating tech debt and a string of recently discovered MV2-specific bugs. Some MV2 code will linger and keep functioning for a while, but Google won’t gate it behind a compilation flag, and it will be removed piecemeal over time.

The change ripples across the Chromium ecosystem. Edge started disabling uBlock Origin in February, and Opera — despite a 2024 pledge to support MV2 longer — has told developers to migrate to MV3 and may have stopped reviewing MV2 submissions, per uBlock Origin author Raymond Hill. Brave, and possibly Vivaldi, remain the holdouts among Chromium browsers, while Firefox continues to support both manifest versions. Chrome users’ main option is uBlock Origin Lite, the MV3 rewrite, which is widely regarded as less capable than the original.