Quickjack allows you to easily perform clickjacking, or steal "clicks" from users on many websites, forcing the user to unknowingly click buttons or links
https://www.owasp.org/index.php/Clickjacking_Defense_Cheat_Sheet

Package managers like Composer for PHP and NPM for Node have become essential tools for simplifying a developer’s life. A package manager is a tool for keeping track of what you’ve installed, as well as installing and upgrading packages. They also check for dependencies and compatibility. Bower is a package manager for the web.

Render beautiful pixel perfect representations of websites in your terminal

Perform the same request against two HTTP servers and diff the results.

Silicon is a high performance, middleware oriented, C++14 http web framework. It brings to C++ the high expressive power of other web frameworks based on dynamic languages without introducing run-time overhead. Its compile-time static metaprogramming paradigm allows to match the performances of servers written in C.

A collection of useful .htaccess snippets.

µBlock is not an ad blocker; it's a general-purpose blocker. µBlock blocks ads through its support of the Adblock Plus filter syntax. µBlock extends the syntax and is designed to work with custom rules and filters.

A high performance, middleware oriented C++14 http web framework.

WebSocket++ is a header only C++ library that implements RFC6455 The WebSocket Protocol. It allows integrating WebSocket client and server functionality into C++ programs. It uses interchangeable network transport modules including one based on C++ iostreams and one based on Boost Asio.

Pour faire une capture d'écran d'une page complète dans Firefox (même si ça dépasse l'écran), appelez la console développeur (MAJ+F2) et tapez: screenshot --fullpage nomfichier
Et cela va enregistrer un png de la page complète. Pas besoin d'addon spécifique !

cheerp is the C++ compiler for the web
Write a web application, or port your existing one, all in C++. cheerp will generate JavaScript code that can run on any browser.