Restrict extensions for "security" reasons. Which just killed most ad blockers in Chrome.

Speed up the web with AMP that gives one company control over everything.

I think security is within the purview of a browser. Even if I disagree with the implementation.

And AMP is not a browser feature.

> What do browsers do that they weren’t meant to?

For example, asking you straight on first launch to log into your Google account, for your "benefit".

In a multi device world that makes sense though. If you save your passwords on your phone, you don’t want to lose them all if that phone breaks.

They're basically sandboxed OSes now. This was discussed at length in the recent Mozilla threads, especially in relation to waterfox and other forks of gecko.