For Firefox and Addons developers: like Scratchpad, this tool comes with a "chrome" mode (type ":chrome" to enable it).
Why? As you know, we already have similar tools in Firefox (Scratchpad and WebConsole). These tools cover some specific use cases. I'd like to explore alternative ways to cover these use cases (code exploration, prototyping, etc). Scratchpad is still much better for prototyping. For the REPL environnement, I think this terminal feels more "comfortable" than the Web Console (which comes with REPL + Logging, which limits the possibilities of the console).
Let me know what you think in the comments (and if you find bugs, please report them on github).(switch the 480p for a better video quality)