Cloudflare's automated SXG pipeline (ASX). Sitting as a reverse proxy in front of the origin, it parses the HTML response, finds all <link rel=preload> tags in head/body, generates a SHA integrity hash for each sub-resource, and adds them to the Link HTTP header of the signed exchange package. Requires appropriate Cache-Control (public, max-age between 120 s and 7 days; higher values are capped at 7 days, lower values skip SXG generation). Enabled with a single toggle in the Cloudflare subscription.