Prioritize: accept media queries on link header.

[andyj2022]

For me it is impossible for it to work, much less claim a performance improvement. For example, in the “link” header we put the image that will be “LCP”, but of course there are several versions of it, and they are distinguished by the use of media queries.

Well, Cloduflare doesn’t support for Early Hints the media query syntax for “link”, and so it’s totally useless, because it doesn’t understand them, due to an error in the Cloudflare link parser, where the media attributes' parentheses and colons are not recognized as a valid link for preloading. In such a way that Cloudflare would force us to use the same image for mobile and desktop, that is, a loss of performance. Hopefully they fix it soon, but they’ve known about it for months and they haven’t fixed it.

A similar matter: we usually discriminate with media queries the preloading of the web fonts. If it is desktop, they are preloaded; if it is mobile, they are not preloaded. With Early Hints, this not run, for the same reason.