CoffeeScript Console 3 is a Chrome add-on developed by Stanford HCI Research Group. It is a console within the Chrome Dev Tools that allows users to write and run CoffeeScript and LiveScript code. It is based on Coffee Console 2 and LiveScriptConsole.

To access the CoffeeScript Console 3, simply open the Chrome Developer Tools by pressing Ctrl-Shift-J (or Command-Option-J on Mac) and navigate to the LiveScriptConsole tab. Once there, users can enter LiveScript code, see it compiled to JavaScript, and run it.

This add-on provides a convenient and efficient way for developers to work with CoffeeScript and LiveScript within the Chrome environment. It is a valuable tool for those who prefer these languages and want to streamline their coding process.