What is Manifest V3?
Manifest V3 is the set of rules Chrome imposes on browser extensions, rolled out progressively between 2023 and 2025. By limiting how extensions can filter requests, it weakens the most effective ad blockers. Firefox keeps the old filtering capability, and Brave ships its own built-in blocker. The topic continues in chapter 2 of my book, Vivre sans Google.
Information verified on July 13, 2026
The house rules Chrome imposes on its extensions. Manifest V3 defines what an extension is allowed to do in the browser: which data it can read, how it can filter pages, within which limits. Google rolled it out progressively between 2023 and 2025, replacing the previous rules, Manifest V2.
The sore point is ad blockers. The new rules cap an extension’s ability to inspect and filter requests, which weakens the most effective blockers, the ones that examined every connection closely. The official argument: security and performance. But who makes Chrome? A company that lives off advertising. Draw your own conclusion.
Not every browser followed. Firefox adopted the new format while keeping the old filtering capability: full-strength blockers still work there. Brave sidesteps the problem another way, with a blocker built directly into the browser, out of reach of these rules.
Where it plays out: chapter 2 of the book explains why the browser is a structuring choice, the Web browsers category reviews the alternatives, and two comparisons detail this exact point: Brave vs Chrome and Firefox vs Chrome.
This topic is chapter 2 of my book
It answers these questions, among others:
- which settings actually make a difference once the browser is installed?
- how do you handle the work computer where Chrome is required?
- and how do Safari and Edge hold up, the ones nobody ever compares?
Forthcoming 22/10/2026 from Éditions Eyrolles
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Tech jargon, translated
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