A look at the growing disparities between ad blocker browser extensions, as Google's Manifest V3 bans blocking via Web Request while Mozilla keeps supporting it
There's a growing split over how much room browsers should leave for ad blocking — and Chrome and Firefox have ended up on opposite sides of the fight.
Context & Ripple Effects
This split has been three years in the making. In mid-2019 Google said Chrome's current ad blocking would be restricted to enterprise users under its new extensions API, then softened the blow by raising the filter rules cap to 150K for blocker developers. Mozilla answered within months that Firefox's Manifest v3 would not follow Google's implementation, preserving blocking via the Web Request API.
The Verge's piece lands as that divergence hardens into user-visible reality: Chrome has begun warning that uBlock Origin may soon be disabled ahead of Manifest V2 deprecation, while Firefox remains the mainstream browser where full-strength blockers keep working. It is also consistent with the earlier privacy fault line, when Firefox and Chromium rivals like Edge, Brave, Opera, and Vivaldi refused to join Google's FLoC cookie-replacement scheme.
First-order effects
- uBlock Origin and other Web Request-based blockers face deprecation on Chrome, pushing their users toward Firefox or Chrome's enterprise channel — the loophole Google flagged back in its 2019 enterprise-only announcement.
Second-order effects
- Chromium-based browsers that already broke ranks on FLoC now face a second fork decision: adopt Google's Manifest V3 wholesale or maintain their own patchset to keep ad blocking alive, raising maintenance costs across Edge, Brave, Opera, and Vivaldi.
Third-order effects
- Extension capability is becoming a competitive axis between browser platforms rather than a shared web standard — the same governance question raised by the cluster of 295 malicious Chrome extensions with 80M+ users, where tighter platform control trades user freedom for supply-chain safety.
The trend: Browser vendors are splitting into two camps over how much low-level control extensions keep, with Chrome tightening its API surface while Mozilla positions Firefox as the last mainstream home for unrestricted content blocking.