Firefox plugin to learn about technologies used by other web sites

Question

Is there a FireFox plugin that tells you what web server (httpd, Tomcat, IIS), platforms (Drupal, WordPress, Rails, PHP, .NET, Java) and client-side (JavaScript, HTML5, Flex) technologies a particular web site uses?

Answer 1

Wappalyzer will do this for many tools.
Note that some may not be possible, and also that there are ways to obfuscate some of them(eg. installing to non-standard locations) that might break detection, depending upon the particular method used.