There are new features (tools adapter, side-by-side profiles, compact theme, developer-friendly default preferences).

But what's larger than any of that is the change in Mozilla's policy / conception of the pre-Beta channel. This is very much a v0 offering, of course, but it's an indication that we genuinely want to take developer feedback seriously and co-design this with you.

We've given ourselves the freedom to ship tools into Developer Edition that aren't yet ready for Beta. We're willing to change the browser's appearance and defaults specifically for a web developer audience.

If you have feature requests, please submit (or upvote) them on UserVoice: https://ffdevtools.uservoice.com/forums/246087-firefox-devel... the DevTools team actively monitors and responds to requests there. Your ideas will get seen, and now, we have even more freedom to actually execute on them.

Hm, so if I develop on this I will still have to test in the regular stable Firefox release, that seems unfortunate.

Having more tools in a developer edition compared to the regular version of the browser seems fine, but at least for me I would like run it with the same rendering engine my users are likely to run.

I don't understand the problem. Responsible web developers test across multiple browsers anyway, and this edition allows you to hook the developer edition tools into other browsers.

I think the idea is Nightly/Aurora/Beta builds aren't just for Firefox Developers but Web Developers too and it would be beneficial if more web developers used this branch for development.

Of course, don't forget to test in stable.

Another thing I can think of is rather than prefixing CSS/JS, experimental features could always be enabled in the developer builds and it then kicks into life on stable when it's ready for the general public. Right now you need to change various flags for that to happen.

It has some addons installed by default (ADB Helper, Firefox Developer Tools Adapter and Web IDE is turned on by default). I like the Firefox Developer tools but it feels like this one isn't that different from a nightly build with some plugins.