Oh, that’s a great point. The first reason is because I don’t spend enough time with HTTP headers, so they aren’t the first thing that come to mind. So this is a great callout. Another is that my assumptions are that we often work with limited information available, so I was trying to share examples of working with nothing. This post was also mostly intended for location details, but that’s a relevant point in the context, and a reasonable thing to expect, so I’ll add a note to the article. Thanks for the contribution :)