I think you missed my main point which is that for a browser to offer a permission-gated flow to website developers, the browser executable itself needs to have

I think you missed my main point which is that for a browser to offer a permission-gated flow to website developers, the browser executable itself needs to have the idle detection system in place. There's no permission to turn _that_ off in the browser itself. It can track your lock screen, and activity outside the browser without prompting you. It's installed automatically by the auto update mechanism. You could argue that Chrome was already doing this and sending that data back to Google over telemetry. (I don't know if they were.) That's where my second point comes in. Before, they had no justification for this. If they do it, it would look like creepy tracking. Now if you call attention to it they can say oh that's just there to power idleness API, nothing to worry about.