@hikari Chrome "Ad privacy" (formerly "Ad sandbox", formerly "Ad labs") comprises three distinct features with individual toggles. You are referring to one of them ("Topics"). However, another one of the three, "Ad measurement", appears to be identical to the feature implemented by Firefox (and Safari, for that matter). Unlike Firefox (or Apple?), Google as far as I know/have tested will not turn any of these three features on without disclosing to the user and giving them a chance to opt out.