This was is out-of order extension (I mean there are several extensions that I use on daily basis and for that reason I planned to mention them before this one) – but it helped tremendously in my BI project, so here it goes.
Live Headers does one thing only and does it well – shows you HTTP headers of a communication between your browser and any Web site. As long as the browser is Firefox – but why would you want to use anything else, right ?.
It sounds simple – but consider the alternatives. What I was doing in such situations before was to set up a logging proxy that would intercept the HTTP Request/Response, log the data (or display them) and copy the request (or response) to the target. Yes it worked, but it is soooo much more comfortable just to click in the menu – compared to unpacking Tomcat, remembering how is the proxy configured, and so on ….