This is served from attacker's Cloudflare account (321d69b731509024febb91ee7e4d7828).
A different account (8837d36895beb5d0a2d506c49e65915c) previously owned this subdomain and deployed legitimate content. They deleted their project; I immediately registered a new Pages project with the same name and inherited the subdomain.
Any user with a pre-registered Service Worker for this origin is now executing attacker-controlled code.