Since the early wars between Netscape and IE, functionality has become the main tool in browser competition. But the strategy of unlimited growth and expansion is completely insane. For too long we have let it go on.
Using wget I downloaded all 1217 of the W3C specifications published to date1. A significant portion of these must be implemented in the browser for the modern web to work. I have calculated the scope of these specifications. How complex do you think the modern web is?
Before the release of Firefox Quantum, there is less time left. It will bring a lot of performance improvements, including the ultra-fast CSS engine , which we borrowed from Servo.
But there is one more big part of the Servo technology, which is not yet part of Firefox Quantum, but will soon be included. This is WebRender, part of the Quantum Render project.

WebRender is known for its exceptional speed. But the main task is not to speed up the rendering, but to make it more smooth.
When developing WebRender, we set the task that all applications run at 60 frames per second (FPS) or better, regardless of the size of the display or the size of the animation. And it worked. Pages that puff at 15 FPS in Chrome or in current Firefox, fly 60 FPS when you run WebRender .
How does WebRender do it? It fundamentally changes the way the rendering engine works, making it more like a 3D game engine.
Today, I would like to talk about Firefox add-ons for the web development that can extend the browser’s core functionality, because I believe that these add-ons are very important for any web developer and web designer.
Many of these add-ons you already know!
Let's start with the most popular and powerful a wed development tool:
1. Firebug

Many people probably know that the latest stable version of Firefox got its own web inspector. Its release was a matter of time, it is potentially very interesting, but now it's not specifically about it. In the 11th version of the browser this inspector will receive an interesting upgrade 3D DOM Inspector. This mode previously could be seen by installing Tilt 3D add-ons. In brief, this thing can visualize the components of the website and view them from different angles, it looks like this:

Firefox is very popular among web developers because of its extensibility through various plug-ins and add-ons that were written by independent developers. The extension idea allowed solving a lot of various tasks directly in the browser without resorting to external tools.
Undoubtedly, you will find the familiar extensions in this list, but a lot of useful extensions always remain aside. So get ready to install a couple more extensions! :)
Built-in developer tools in Firefox
Fist we would like to mention the tools already built into Firefox. This article introduces a collection of development tools in Firefox Aurora 10 that could be found in any modern browser.
Mozilla has tried many approaches and solutions during the interface designing of these tools. Consequently, they got a nice interface that anyone can try by installing Firefox Aurora (Have you installed it yet?)

You will find below a big list of extensions, which is going to be useful for any web developer.