HTTP headers / response header
Accept-Ranges: bytes
Advertises that the server supports Range requests on this resource.
Absence does not forbid trying a Range — but a server answering 200 with the full body to your Range request is telling you it does not care.
The fastest way to see what Accept-Ranges is actually doing is to send the request and read both sides raw — ReqPad shows auto-generated and custom headers for every request, on all six protocols, with history. Related references: status codes · WWW-Authenticate · Content-Encoding · Transfer-Encoding · ETag · Last-Modified · Expires
Build the request, send it, read raw headers and timing — from your iPhone. Free to start.