I assume this was prompted by the battery status information leak. That sort of behaviour is likely illegal under EU privacy regulations without explicit concen

I assume this was prompted by the battery status information leak. That sort of behaviour is likely illegal under EU privacy regulations without explicit concent. In firefox, you can disable this nasty behaviour by editing the "dom.battery.enabled" setting in about:config. IMO this should be a MUCH more obvious setting in the settings menu, along with any other information that can be accessed without concent.