A web page that tells you what your browser gave away the moment you arrived. No login, no form, no permission. Most pages do this. None of them tell you.
Shouldn’t that be the provenance of the device itself though. My phone already allows me to set a threshold when it should go to night mode for example. The system can tell the browser to switch rendering to night mode. There’s no real reason for the browser then to report to the site.
I can understand the latter since it might want to render differently, but why does it need to know the battery level?
Potentially to activate battery-saving features? Like AMOLED-black mode if your battery is <15 % or something (and your screen is AMOLED)
Shouldn’t that be the provenance of the device itself though. My phone already allows me to set a threshold when it should go to night mode for example. The system can tell the browser to switch rendering to night mode. There’s no real reason for the browser then to report to the site.