I appreciate that @github is changing the site's favicon in response to the system's light/dark color scheme (probably drafts.csswg.org/mediaquerie…). It's improved the UI for me (dark theme). Though it looks like they're using JS to change the <link rel=icon> links. 1/3

It seems like it should work if they used (prefers-color-scheme) media queries inside of their SVG favicon. I wouldn't be surprised if it doesn't work. In fact, I'd probably be surprised if it worked across browsers... 2/3