> JS to persist the setting.
Yes, local storage is crucial functionality. I don't get people who disable JS, but I suppose if they have a bunch of sites they whitelist it's less painful... but then they must trust those sites all the time? How do they know if those sites haven't installed new scary scripts?
Perhaps one possible solution is for browsers to offer a setting to enable all the "safe" functionality of javascript such as button events for fancy carousels, but block the stuff that causes anxiety. I suppose then we'd all argue about what aspects are safe vs scary.
DevTools in Firefox and Chrome both have a `prefers-color-scheme` override built in, no extension required.
For testing there are extensions which allow overriding the browser’s scheme (for Firefox anyway).