The site sends no `content-type` handler. I'd expect the networking code to sniff. That part of the web is under-specified in terms of compatibility, so I don't know if there's just a sniffer difference between chromium/blink (Edge) and gecko in terms of how they determine text/plain vs. non-text here - but that's somewhere in networking code, so moving over there.
Bug 1875646 Comment 4 Edit History
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The site sends no `content-type` header. I'd expect the networking code to sniff. That part of the web is under-specified in terms of compatibility, so I don't know if there's just a sniffer difference between chromium/blink (Edge) and gecko in terms of how they determine text/plain vs. non-text here - but that's somewhere in networking code, so moving over there.