The Firefox debugger that works anywhere
"A hackable debugger for modern times, built from the ground up using React and Redux. It is designed to be approachable, yet powerful. And it is engineered to be predictable, understandable, and testable.
Mozilla created this debugger for use in the Firefox Developer Tools. And we've purposely created this project in GitHub, using modern toolchains. We hope to not only create a great debugger that works with the Firefox and Chrome debugging protocols, but also develop a broader community that wants to create great tools for the web."