[mnot]

Ah - I need to remember to coffee before posting in the AM.

Yes, the mismatch between the response headers and the content is a problem. Unfortunately, IME browsers often do "fix ups" of headers that make them less than reliable, this might be one of them -- it's effectively rewriting the response but failing to update all of the metadata.

The bug summary says "Chrome returns wrong status code while using range header with caches." That's indeed not a bug. I think the most concerning thing here is that the Content-Range header is obviously incorrect, so Chrome should either be updating it or producing a clear error to alert you -- which it looks like the Chrome dev acknowledges when they say "it is probably a bug that there is no AbortError exception on the read".

I might try to add some tests for this to https://cache-tests.fyi/#partial