BuiltWith - Find out the technology behind websites

Zenity - Zenity is a tool that allows you to display GTK dialog boxes in commandline and shell scripts.

Wappalyzer - Wappalyzer is a technology profilers and leads data provider. Create lists of websites and contacts that use certain technologies.

Glade - Glade is a RAD tool to enable quick & easy development of user interfaces for the GTK+ toolkit...

WhatRuns - Extension that helps you identify technologies used on any website at the click of a button.

Yad - Yad (yet another dialog) is a fork of Zenity with many improvements, such as custom buttons...