I did some research on range requests, and everything's inconsistent https://docs.google.com/document/d/1SphP-WNxqzZrSv_6ApC9_FpM-m_tLzm57oL3SNGg-40/edit#heading=h.1k8r6xdc6vfo

The only reliable way of streaming video across browsers is for the server to return exactly the range requested. It feels like it's expected, and faster, for cache.match(request) to generate a 206 (or 416) if the request has a range header.

It'd be great to do this for opaque responses too, where the generated 206/416 would also be opaque, but I'd like a security person to weigh in there.