Since January, Google has been pushing for a change to its extensions handling in Chrome; one casualty of that change is ability to block unwanted content before its loads, something that would effectively kill privacy tools and ad-blockers.
After a public outcry, Google has tweaked the change, but only for enterprise customers, who will have access to an API that will allow this kind of blocking. That means that corporations will be able to develop internal-use plugins that do the kind of screening that adblockers do for the rest of us today.
Google has warned investors that "New and existing technologies could affect our ability to customize ads and/or could block ads online, which would harm our business," and ad blocker developers like Raymond Hill of Ublock Origin have speculated that "Google's primary business is incompatible with unimpeded content blocking. Now that Google Chrome product has achieve high market share, the content blocking concerns as stated in its 10K filing are being tackled."
Google denies this, and says "We're actively working with the developer community to get feedback and iterate on the design of a privacy-preserving content filtering system that limits the amount of sensitive browser data shared with third parties."
Chrome is the dominant browser on the web today, and even though it is nominally open source, Google has used a suite of tricks to ensure that it gets to decide who can adapt it and what features those adaptations can have.
Firefox is available for virtually every OS — mobile and desktop — and supports full ad-blocking.
Chrome is deprecating the blocking capabilities of the webRequest API in Manifest V3, not the entire webRequest API (though blocking will still be available to enterprise deployments).
Google is essentially saying that Chrome will still have the capability to block unwanted content, but this will be restricted to only paid, enterprise users of Chrome. This is likely to allow enterprise customers to develop in-house Chrome extensions, not for ad blocking usage.
For the rest of us, Google hasn't budged on their changes to content blockers, meaning that ad blockers will need to switch to a less effective, rules-based system, called "declarativeNetRequest."
Chrome to limit full ad blocking extensions to enterprise users [Kyle Bradshaw/9to5Google]