It gives extension developers less control and flexibility, making some features more difficult or simply impossible. Notably, it nerfs functionality that ad bl

It gives extension developers less control and flexibility, making some features more difficult or simply impossible. Notably, it nerfs functionality that ad blockers rely on, so the suspicion is that's pretty much the only reason the change is being made. This will impact you because your ad blocker will suddenly not do as good a job blocking ads, or be more cumbersome to use. The upside is some poorly behaved extensions will have less impact on browser performance.