You mean the thing that is not actually supported in any browser other than Chrome, because Google just came up with it a few months ago to replace <link rel="p

You mean the thing that is not actually supported in any browser other than Chrome, because Google just came up with it a few months ago to replace <link rel="prefetch">, which worked in most brosers? (Yes, I know Safari technical preview has support, but shipping Safari does not. We'll see whether Firefox ends up shipping support before Safari or not; the patches to implement <link rel="preload"> in Firefox got posted to https://bugzilla.mozilla.org/show_bug.cgi?id=1222633 https://bugzilla.mozilla.org/show_bug.cgi?id=1222633 earlier today.)