Comment by vinceguidry

> Each site should not have to reinvent this feature.

This would send me into peals of laughter if I weren't already crying. The time to make this argument was 30 years ago, when the web wasn't fragmenting into a billion different pieces. The browser can make exactly zero assumptions about any given site, so it could never be a place where user preferences about them could be actionable. Downvoters should get work as web developers sometime. You really want the browser making assumptions about your web design?

All it can do is pass a header and let the website do what it will with it.