Just to be clear, "Battery Status" is not a "W3C spec". The latest published version at https://www.w3.org/TR/battery-status/ https://www.w3.org/TR/battery-sta

Just to be clear, "Battery Status" is not a "W3C spec". The latest published version at https://www.w3.org/TR/battery-status/ https://www.w3.org/TR/battery-status/ is "Candidate Recommendation", and has been stuck there for over four years, precisely because it's failing to meet the bar to progress to "Recommendation". And the reason it's failing to meet that bar is because of fundamental and unaddressed privacy problems with the proposal. Calling it a "Chrome proprietary API" is exactly correct at this point.