C++ - Has imperative, object-oriented and generic programming features, while also providing the facilities for low level memory manipulation
BuiltWith - Find out the technology behind websites
D (Programming Language) - D is a language with C-like syntax and static typing.
Wappalyzer - Wappalyzer is a technology profilers and leads data provider. Create lists of websites and contacts that use certain technologies.
Perl - Highly capable, feature-rich programming language with over 26 years of development
What CMS - WhatCMS.org looks at a variety of factors within a webpage to determine what CMS a website is using.