I was doing a little bit of work earlier and I needed to look up some info on the Content-Type header. When doing searches like this here's a quick tip that will help you get really good information:
Prefix your searches with the string "mdn"
So in my case I googled "mdn Content-type". This will lead you to the relevant article on the Mozilla Developer Network. This is by FAR the best reference on basic web tech. Consider this the Encyclopedia Brittanica of the web. It's always best to start here, then broaden your search if you need more.
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