Comment by coldpie

Are you talking about the color scheme of the webpage, not the browser UI? The thing reported by the prefers-color-scheme hint[1]?

Building a whole user interface to declare the setting of that preference per-site seems like a pretty high cost for something that won't be used by very many people. Most people just want the site to match their current preference. Instead, websites usually provide a way to override the setting which is stored as a cookie or whatever. I think overriding that value belongs in an extension, not as a core browser feature.

[1] https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/A...