WhatWeb fingerprints Web servers and Web applications. It can identify content
management systems (CMS), Web application frameworks, default pages for Web
servers, blogs, JavaScript libraries, and more.... Each time you visit a Web
site in your browser, the Web server leaks many hints about the software
delivering the Web page. WhatWeb recognizes these hints and reports what it
finds. WhatWeb has over 70 plugins. Plugins can identify systems with obvious
signs removed by looking for subtle clues. Plugins are flexible and can return
any datatype. For example, plugins can return version numbers, email addresses,
account IDs, and more