“Like FLoC and Privacy Sandbox before it, Manifest V3 is another example of the inherent conflict of interest that comes from Google controlling both the dominant web browser and one of the largest internet advertising networks.”
Google says Manifest V3 is about security and performance. Princeton and Chicago researchers found privacy extensions make browsers faster. The rules cripple tracker blockers. Google has trackers on 75% of the top million sites. The ad company is writing the rules for the ad blockers.