Mozilla is moving away from its Firefox tools away from XML User interface Language (XUL) in using Redux and react. A modern architecture of Redux Store model and reusable React component is what all Firefox DevTool are transitioning towards and away from XUL. With only Firefox supporting it XUL is effectively proprietary and yet open. The previous debugger was extremely tough to change and much of this because of XUL. View components that frequently avoids even simple changes from being easily attained, XUL is a spider web of the model. Code are simplified into smaller modules using Redux and React. All of our future developer tools will be more predictable, approachable, testable and understandable with the help of this.