lucy24 - 2:40 am on Mar 11, 2013 (gmt 0)
Live Headers is a Firefox add-on. I think there are equivalents in some other browsers, but Live Headers is the best known.
Essentially it gives you-as-user the same information the site owner gets. There's a text file that shows each consecutive browser request followed by the full response. So you'll see all your 301s and 404s and whatnot. It doesn't (and can't) show server-internal activity like includes and rewrites.
Tip: Unless you particularly need to track requests for peripheral files, I suggest going to the Config tab in Live Headers and set the "Exclude URLs with regexp" line to read something like
That way, all it tracks is requests for pages. In most situations, that's all you are interested in.