Most servers just read the preload headers from the backend and use that as a push. That won't work with "HTTP 103 Early Hints" (Since it needs to know what to

Most servers just read the preload headers from the backend and use that as a push. That won't work with "HTTP 103 Early Hints" (Since it needs to know what to push before the backend responds), but for now a preload header is a good compromise between ease-of-use and good-enough.