DOM Monster Bookmarklet : DOM Monster is a cross-platform, cross-browser bookmarklet that will analyze the DOM & other features of the page you're on, and give you its bill of ...
wuzz : Interactive cli tool for HTTP inspection
Wuzz command line arguments are similar to cURL's arguments, so it can be used to inspect/modify requests cop...
manifestR is a bookmarklet, which you drag to your bookmarks bar. Then, when you visit any page, you can click the manifestR button, and it will create an HTML5 appcache manifest file for that page.