Google has tweaked a proposal on how future versions of Chrome will deal with ad blockers following an outcry from developers.

In a post on Google Groups, Google software engineer Devlin Cronin revealed one change designed to address criticism over a proposal on how Chrome will treat ad blockers and other extensions. Through the proposal, known as "Manifest V3," Google had floated the idea of restricting ad blockers by making them consult a database containing just 30,000 entries. Though that seems like a large number, such a limit would've broken certain ad blockers, which may consult hundreds of thousands of entries to determine what to block.

Cronin said that Google will raise the limit beyond the draft 30,000 number, although he did acknowledge that some limit will be necessary, saying that "having this list continue to grow unbounded is problematic."

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As the leading Web browser, Chrome has attracted a growing list of extensions designed to enhance its capabilities. But not all extensions are safe, secure and reliable. Google's Manifest V3 proposal is an effort to improve the performance and security of Chrome extensions. In the case of ad blockers, Google had contended that ad blockers cause web pages to load more slowly in Chrome as the browser has to check a large database of blocked sites. Restricting the number of such sites would be Google's solution to improving performance.

But limiting the number of entries to 30,000 would've clobbered ad and content blockers such as Ghostery, uBlock Origin and NoScript, prompting the developers of these extensions to criticize Google's proposal. Furthermore, a study conducted by the people behind Ghostery in response to Google's claims found that ad blockers had only a sub-millisecond impact on each web page request in Chrome. A previous study run by Ghostery found that ad blockers reduced the load time of websites by up to a factor of 2.

Ghostery's developer had threatened legal action against Google had the proposal stood and gone forward.

"This would basically mean that Google is destroying ad blocking and privacy protection as we know it," the company said in a recent blog post. "Whether Google does this to protect their advertising business or simply to force its own rules on everyone else, it would be nothing less than another case of misuse of its market-dominating position. If this comes true, we will consider filing an antitrust complaint."

In his post, Cronin also reminded people that the Manifest V3 proposal is still in draft mode and that more needs to be done before it is finalized.

"I'd like to reiterate that all of these changes are still in the draft and design stage, as explicitly called out in the document and the tracking bug," Cronin said. "The declarativeNetRequest API [the API that would've broken ad blockers due to the proposed limits] is still being expanded and is under active development, and the exact changes that will be implemented as part of Manifest V3 are not finalized. Feedback during this time is crucial, and we absolutely want to hear your comments and concerns."

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  • Google has revised a proposal that would have broken many ad blockers by severely limiting the number of sites they can block.
  • Google's Manifest V3, a proposal to improve the performance and security of Chrome extensions, had earned criticism from developers over the ad blocking restrictions.

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Lance Whitney is a freelance technology writer and trainer and a former IT professional. He's written for Time, CNET, PCMag, and several other publications. He's the author of two tech books - "Windows 8 Five Minutes at a Time" and "Teach Yourself VISUALLY LinkedIn."