waybackpack : Waybackpack is a command-line tool that lets you download the entire Wayback Machine archive for a given URL.
Web Developer : The Web Developer extension adds various web developer tools to a browser. The extension is available for Chrome, Firefox and Opera, and will run on a...
InstantClick : InstantClick is a JavaScript library that dramatically speeds up your website, making navigation effectively instant in most cases.
PURLs are persistent URLs, they provide permanent addresses for resources on the web.