Specification: https://html.spec.whatwg.org/multipage/links.html#link-type-preload
Background: https://developer.mozilla.org/en-US/docs/Web/HTML/Attributes/rel/preload

Broken web content: https://thp.org/
Tests: ./mach test-wpt tests/wpt/tests/preload/