✔ DONE - DevTools Fission M1
Multiprocess Browser Toolbox

Migrate the most important tools (debugger, inspector, console) to the new multi-process-aware architecture inside the Browser Toolbox.
This allows us to prepare DevTools for Fission, while making the Browser Toolbox (and the Browser Console) much more useful to Mozilla engineers.

DevTools Fission M2
Fission support for Web Developers

Make the necessary changes for the Content Toolbox to support Fission.
Get all tools ready to support navigation process switches.
Implement new UI to switch JavaScript execution context in the tools.

✔ DONE - RDM Fission

Stop relying on the <iframe mozbrowser> element, and embed RDM in the browser front-end code directly.