Comment by greyface-
Yes. https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Re...
In a similar vein, you can also use `Link: foo.css; rel=stylesheet` instead of `<link href="foo.css" rel="stylesheet" />` to specify stylesheets. https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Li...
Only works in Firefox, sadly. But you can do some really weird stuff with it, like https://www.5snb.club/pages/contentlesshtml/ (https://news.ycombinator.com/item?id=42234837)