Once installed, the extension will add a small icon to the address bar. Clicking it gives you access to more than twenty different tools and utilities, such as viewing the source code of a page, the alternative text, or just the images.
The extension also has a good amount of options that allow you to establish keyboard shortcuts for each important function. That means that you could, for example, select one color of the webpage that you're viewing with just a tap of the keyboard.
Pendule is geared toward developers, who will surely find more ways to use it than your average browser. Still, anyone who is frequently on the Internet will probably find some features useful.