Google makes moves to block ad blockers, and it’s doing it all for you

Proposed changes to the open-source Chromium browser could break content-blocking extensions, breaking various ad blockers.

This all comes from Manifest v3, which is the specification for browser extension manifest files. These lay out exactly what resources and capabilities are made available for use by browser extensions in Chromium. Chromium is currently the core of the popular Google Chrome browser, and will soon be the basis for the reworked Microsoft Edge browser.

Google’s reasoning for the changes is improved security, privacy and performance. There’s no mention of Google’s primary business as a purveyor of advertisements, something hindered by third party ad blocking extensions.

The big part of the change is that Google intend to change the webRequest API with declarativeNetRequest. WebRequest allows ad blocking extensions to intercept network requests, letting them be blocked, modified or redirected. As the browser has to wait for the extension to finish before it can load up the page.

As a result, webRequest will only be able to read the network requests, and not modify them. Bad news for content blocking extensions as it will be the Chromium browser that decides how to deal with network requests rather than extensions.

You can track the proposed changes on the Chromium tracker here, but it’s worth noting the response from Raymond Hill, better known by his online alias Gorhill, the man behind uBlock, Origin and uMatrix, a trio of popular blockers.

“If this (quite limited) declarativeNetRequest API ends up being the only way content blockers can accomplish their duty, this essentially means that two content blockers I have maintained for years, uBlock Origin (“uBO”) and uMatrix, can no longer exist.”

“There are other features (which I understand are appreciated by many users) which can’t be implemented with the declarativeNetRequest API, for examples, the blocking of media element which are larger than a set size, the disabling of JavaScript execution through the injection of CSP directives, the removal of outgoing Cookie headers, etc. — and all of these can be set to override a less specific setting, i.e. one could choose to globally block large media elements, but allow them on a few specific sites, and so on still be able to override these rules with ever more specific rules.” 

There will still be basic ad filtering technology such as that attached to Chrome and third-party extension AdBlock Plus, but even though will be less useful then before due to a cap on the amount of network filters available, locking it down to 30,000.

However, AdBlock Plus has reached out to Trusted Reviews with its own statement, claiming they will also be impacted by the changes. “Adblock Plus is of course affected by this proposed change, because it would replace the main API that we (and almost all other content blockers) use to block requests with something a bit more watered down,” said a spokesperson for AdBlock Plus. “Even though we don’t know the exact plans for this proposed change, should it get implemented we’ll make sure ABP is available for Chrome users.”

This is still a proposed change and the backlash has been severe, so we may say a change in the way this is actually implemented, however the suggestion of a change has already got many gripping their pitchforks and ready to swear allegiance to a new browsers.

We’ve reached out to Google for comment.

Would you switch browsers if adblocking was, well, blocked? Let us know on Twitter at @TrustedReviews