What is Reddit's opinion of
Firefox Nightly?
From 3.5 billion Reddit comments
77 reviews of this app found across Reddit:
the scrolling is fixed in the nightly builds.
Its uses native android scroll physics - https://nightly.mozilla.org/
It will come to stable once its ready for primetime
You can install/run multiple channels without problems as well.
Note: enable telemetry. Helps development
EDIT: Aurora channel as well
All Firefox forks are very similar to Firefox, as they're completely based on it, except for Pale Moon. So it's logical that the original is better.
Edit: You may want to try Nightly, the latest version of Firefox, which you may notice that it's better in comparison to the stable version. https://nightly.mozilla.org/
Thank you. Keep rockin' the free web. :)
(Also +1 for Debian!)
Depending on his desktop environment of choice, he might be interested in trying out a nightly build, which are just starting to switch over to using GTK3.
Does it happen on https://nightly.mozilla.org ? If so and you have steps to reliably replicate the issue, please file a bug as detailed on https://developer.mozilla.org/en-US/docs/Mozilla/Performance/Reporting\_a\_Performance\_Problem
- Example gif/gifv would be great. What device/android version?
- YouTube stopped sending Firefox a unique page and is now treated the same as other mobile browsers. An extension like "I Love Apps" or similar could restore behavior.
- The oom issue has been a plague, there was a recent change on nightly that is likely to reduce the chance of that happening. builds at https://nightly.mozilla.org
- zooming out should be fixed in this release https://bugzil.la/1233762
If you use Firefox and Duck Duck Go I'm assuming you're a privacy concious person. Chrome is obviously not the answer for you. While the sync is cool, Firefox has Firefox Sync. There's not really much of a difference at that point between the major browsers and few are open source and as privacy conscious as the Mozilla team.
With that said, I run Firefox Nightly which is a couple versions ahead. You do get the occasional quirk, but it's typically fixed in the next day's update.
Imo the best way to install nightly is to download the .tar.bz2, extract it somewhere like /opt and point your shortcuts at it. Firefox updates itself very unobtrusively these days.
No white flashes for me in new tabs on latest Nightly. Make sure you have enabled dark mode in your OS or go to about:config and create ui.systemUsesDarkTheme with value 1.
Extract the Mozilla build from https://nightly.mozilla.org to somewhere like ~/nightly. Quit Firefox and run ~/nightly/firefox -P which will allow you to make a second profile. Run that for a bit and see if the crashes still happen.
Yes.
Or run Nightly or Developer Edition. I run the latter to good effect. It's stable and I still get the latest security patches without bothering about manual updates. (Also has a slick optional theme if that floats your boat.)
"According to a Microsoft answer desk advisor, the automatic download is built-in to Edge."
Firefox is running like a dream on Windows 10 https://nightly.mozilla.org/ https://www.mozilla.org/en-US/firefox/channel/ You should check it out, as an added bonus is does not auto-download viruses without first prompting you to accept.
This requires a little bit of context. The developers of the Firefox (Mozilla) and Chrome browsers have cooperated for some time to create the WebVR specification, which allows access to head tracking data etc. from VR devices like the Oculus Rift from within a browser. By using this and other web technologies like WebGL (hardware accelerated OpenGL accessible from a browser), it is possible to create "web sites/apps" that are VR environments. This is a very interesting option, even though currently performance is much lower than native VR apps.
I've posted a longer [introduction to WebVR](/r/GoogleCardboard/comments/3300ho/webvr_support_in_nightly_firefox_for_android/) in April, when WebVR support was introduced into the nightly versions of Firefox for Android. You'll still need to manually install the APK for the nightly Firefox to try at least some of the projects listed on the mozvr.com site with Cardboard. Most won't run, as compatibility between the different implementations is still a big problem. Check /r/webvr for more on what is happening with web based VR.
Might be Bug 1725555 which was fixed in latest Nightly. It would be good if you could download and test it to confirm.
about:performance is limited to what javascript sees, the full memory profile is visible in about:processes and about:memory. Firefox stable reuses processes so there is a memory effect of past tabs. You might want to try Nightly which isolates tabs into processes and terminates them when tabs are closed like Chrome.
Please give WebRender (Firefox' new graphics engine) a try: https://nightly.mozilla.org, open about:config, set gfx.webrender.all to true and restart Nightly.
You might want to use https://nightly.mozilla.org. Begin with a fresh profile (open about:support, click on Refresh Nightly) and enable gfx.webrender.all on about:config (Nightly restart needed). If you then still have any problems it is far easier for the developers to narrow down and fix an issue. WebRender is the new graphics engine. On about:crashes you can see past crashes. If you click on one and go the "Bugzilla" tab you can see if someone else had the same crash and if the developers already know what's going on.
Note that you can still get a Play store-less copy at https://nightly.mozilla.org which will install Firefox Nightly app id org.mozilla.fennec_aurora. The app Nightly org.mozilla.fennec no longer gets updates. It was only available from the Mozilla download site.
cc /u/Tortino2
Also, I'd recommend to give Nightly a try for speed testing. It has the latest and greatest enhancements which are performing really well, much better than the current Firefox stable versions!
You can download Nightly for Android on https://nightly.mozilla.org/ :) You need to enable installations from out the Play Store though, and it will use its own update mechanism, which gives you a notification when a new update is available.
That being said: if you don't like living on the edge and really hate crashes, Nightly is probably not for you. Beta should be pretty stable, so go for it!
Looks like this is a bug within Firefox:
https://bugzilla.mozilla.org/show_bug.cgi?id=1161349
Apparently it has been fixed as of Firefox Nightly 49.0+. https://nightly.mozilla.org/
Worth giving it a try if it bothers you that much.
here you go - https://nightly.mozilla.org/
Reminder these are test build - sometimes they crash, updated almost daily, latest features.
If you want stability - stable or beta is best.
I've got both nightly and beta installed just in case
This will only work for a release unless the user is on Nightly or Developer Edition. This change is to combat malware and 3rd party extensions installed by other software on your computer.
The updater does not work for self installed release or beta builds. You would need to download the Aurora or Nightly build to get automatic(ish) updates.
VAAPI is broken in 80. Please use Beta 81 or Nightly 82.
When using MOZ_X11_EGL=1 you are also using DMABUF WebGL (the pref is enabled since 79): bug 1659350 has been fixed in Nightly 82.
Try the instructions at https://mozvr.com/#rift and let me know where you get lost.
WebVR Plus is optional now for Firefox Nightly (it just sets a flag for OpenVR/Vive support).
If you don't like the debugger, check out the new one in Nightly.
I understand your point of view, I feel that Chrome's debugger is lacking :) It's a matter of personal preferences. Users shouldn't suffer because of your personal preferences.
See Signing and distributing your add-on. If you want to be able to install your addon without entirely disabling the signing requirements, you'll have to get the addon signed by mozilla, which can be automated I think. For personal addons that you're just playing with, you can have it be unlisted.
If you want to install unsigned addons (ie, addons from anywhere including self-built), then you either need to build it yourself or you need to use the developer or nightly edition; these versions will update automatically and will allow you to install unsigned addons after setting xpinstall.signatures.required to false in about:config. (Nightly updates daily on android, but I think the desktop version only updates weekly)
Edit: I just got my own addon signed, and it's very quick and easy, provided the file sizes work well with your internet connection. Just grab an API key and use it to sign your xpi with jpm. You'll get a signed .api file in return, and can install that in firefox.
Yes, the official Chrome dev branch doesn't have WebVR built into it yet. The only way to get WebVR in Chrome right now is to side-load one of the experimental builds that Brandon Jones at Google is working on right now: http://blog.tojicode.com/2014/07/bringing-vr-to-chrome.html. Alternative, there is also Firefox Nightly: https://nightly.mozilla.org/. Both require enabling a flag to turn WebVR on.
Regardless, I put regular motion-controls back in last night. It should work in most mobile browsers now. That particular code path is buggy, though. The various browser vendors don't implement the Device Motion and Device Orientation APIs with the same origin or range of values. My code tries to compensate and renormalize it, but I don't have a wide range of devices on which to test. A WebVR-enabled browser will be more reliable and have smoother tracking.
> in Ubuntu I've also tried Nightly from a PPA that's presumably run by Mozilla
https://help.ubuntu.com/community/FirefoxNewVersion says:
> Users of recent Ubuntu releases can get the latest development version of Firefox from the semi-official ubuntu-mozilla-daily archive
so no, not run by Mozilla. It's also been stated before that if a dist want packages then they'll have to handle them themselves.
Make sure to also check the official Nightly builds, in case Ubuntu has set some strange build flags for their packages.
I'm not sure how the whole graphics stack is put together but some quick reading seems to point to applications having to skip X11 if they want HWA on RPi, so you could try these two:
Set
about:config?filter=gfx.xrender.enabledtofalseand restart Firefox/Nightly. As a footnote, I have this set to false on my desktop system.If that doesn't help then try switching over to skia by setting these two to
skiaorskia,cairo:about:config?filter=gfx.*.azure.backends
Which dist are you running on the RPi2 by the way?
I filed https://bugzilla.mozilla.org/show_bug.cgi?id=1184897 based on this and the other comments.
Edit: it'd be useful if someone who was seeing this could re-test using nightly ( https://nightly.mozilla.org/ ) and report on the bug whether it's fixed there.
Firefox Nightly on Android with Mobile Image Blocker. Nightly supports Firefox Tracking Protection and is running better than Firefox stable for me. Mobile Image Blocker and Tracking Protection reduced my mobile data usage greatly.
Is it a matter of responsiveness whenever you use your finger to swipe and move things around?
It would be interesting to know if Nightly behaved better as it may have vsync enabled.
Clear cache periodically, alternatively try the nightly build. There is a Enable E10S option that you may wanna try to see if it works for you.
Firefox for Android supports html5 video.
There are no requirements when it comes to the codec to support. It is recommended that the codecs be selected from OGG video, WebM and H.264 but they are not mandatory. On all devices Firefox for Android can decode OGG and WebM. On many phones decoding of H.264 is possible. In some cases due to identifiable crashes decoding of H.264 is disabled on Firefox for Android for that specific device.
For modern Android devices (4.1+ I believe) we have made a significant rearchitecture of how H.264 is decoded. As of right now this is only available on Firefox Nightly. https://nightly.mozilla.org and would fix the OP's issue assuming their phone meets the minimum requirements.
Can you provide a crash ID from after you disabled hardware acceleration? Also can you install Firefox Nightly and let us know if you crash there too and if so please provide a crash ID
Lest anyone be confused, the PPA builds are just Ubuntu's compiles of the Firefox code -- Mozilla isn't involved, an afaik there are no modifications. You can get the same thing earlier from http://www.mozilla.org/en-US/firefox/aurora/ or https://nightly.mozilla.org/, albeit in non-package form.
I don't really use firebug anymore, as it's kind of antiquated. I'm sure it's possible, I just don't know how exactly. I usually use Chrome debugger or Firefox Nightly's debugger. Nightly is nice. The top-bar is chromier, which I like, all text is anti-aliased by default, pretty syntax highlighting in the debugger... It's good. In nightly, you just press F12 and click the debugger tab, all the scripts - inline or otherwise - are on the left.
To install permanently, use Developer Edition or Nightly, set xpinstall.signatures.required to false in about:config and add gecko id to your manifest.json.
Does it work on latest Nightly?
Run mozregression between 91 and 95 to find when it stopped working.
sudo apt install python3-pip pip3 install mozregression ~/.local/bin/mozregression --good 91 --bad 95
Download https://nightly.mozilla.org, set media.ffmpeg.vaapi.enabled to true, you don't need to change other media prefs anymore (and you should not because VAAPI now only works with default config). If it doesn't work, open about:support, click on "Copy text to clipboard", file a bug and paste it into the "Add an attachment" field on https://bugzilla.mozilla.org/enter_bug.cgi?product=Core&component=Widget%3A%20Gtk . Thanks!
To get kdeconnect to launch through Wayland you likely need to export QT_QPA_PLATFORM=wayland-egl somewhere because Qt still annoyingly defaults to X11 if you don't force it to use Wayland.
EDIT: For Firefox you'll need a recent version of it (maybe even a Nightly version) because there was an Nvidia specific bug that only got fixed recently.
I don't see that issue either but I'm running Nightly (84.0a1) instead of the stable Release build (/u/uploading_coffee might want to check if it still occurs on Firefox Nightly).
Hardware rendering is still disabled, but WebGL is enabled by default for open source Mesa (Intel, AMD, Nvidia) and proprietary Nvidia.
WebRender is enabled by default for Mesa 18+ on Nightly. If you have integrated Intel/AMD graphics or a dedicated AMD graphics card, you can also profit from hardware video decoding (widget.wayland-dmabuf-vaapi.enabled) and zero copy WebGL (widget.wayland-dmabuf-webgl.enabled) on Wayland. Nvidia should increase its contributions to Nouveau, the open source Mesa driver for Nvidia.
Linux didn't get much QA anyway (if you're a Linux user and you don't mind experimental software please do your fellow penguins a service and install Nightly and report any bugs or crashes you encounter).
Hey, following up here -- can you let us know any downloads where you saw the blank dialog box besides the one you already shared? Developers would like to dig into this further.
Also, any chance you can see if the issue persists in Firefox Nightly?
a) Hardware acceleration is not enabled by default on Linux: Open about:config, set layers.acceleration.force-enabled to true and restart Firefox. b) You could also try out Firefox' new graphics engine: WebRender. https://nightly.mozilla.org, open about:config, set gfx.webrender.all to true and restart Nightly.
Please use https://nightly.mozilla.org and set gfx.webrender.all to true. You get WebRender changes (bug fixes and regressions) everyday with Nightly, but only once about a month with Beta.
Before reporting a performance problem they should try a recent build, ideally nightly in a new profile. The behavior and features of ESR 60 were largely set when it moved to beta in March of 2018.
We've got a lot that needs doing, and we'd be grateful for your help. The Contribute page has a few places to get involved with the Mozilla community, but if you're interested in jumping directly to the technical contribution side of things we've got a lot of choices there as well.
The easiest first step - and one we'd like as much help as we can get with, right now - is to use our Nightly builds for your day-in, day-out browsing. We've got a major release coming up, and the more people we can get beating on our code with routine, real-world browser usage, the better that release is going to be.
And if you run into problems, sign up for a Bugzilla account and file them. That's pretty much step two. They may be duplicates, but don't let that stop you! We'd rather hear about a bug twice than not at all.
There are a few ways to get further involved, depending on what suits you, and what sort if itches you want to scratch. We have a lot of what are called "good first bugs" in Bugzilla - bugs where the challenge isn't really fixing the bug, but getting your development environment set up and learning how our processes work. Often fixes can be as little as a few lines, but once you're set up to make them and push the patches up, you're ready to take on bigger things.
This page should have enough information to get you started - if it doesn't, that's a bug! File it! - but you're welcome to email me with questions. I'm mhoye at mozilla dot com, and if I can help you find your way through that process I'd be happy to.
Thank you for asking, though; we've got a lot of work to do, and we can use all the help we can get.
> Which is why I am more likely to point people to the Developer Edition.
Please help me clear it up, i'm a bit lost.
Are unbranded builds (https://bugzilla.mozilla.org/show_bug.cgi?id=1290548#c9) different from Nightly (https://nightly.mozilla.org/)?
Does Nightly have the add-on sign checking?
I'm curious as to how you installed Nightly on Fedora. On Ubuntu there is an official Mozilla PPA, but I haven't been able to find an equivalent - did you just install from the tarballs available here?
Thanks for contributing in anyway possible.
Users like us are the best feedback!
To mitigate scroll issues - check out Nightly version; its a testers version tho.
Officially, you need a WebVR-enabled browser. That could be one of the experimental Chromium builds that Brandon Jones at Google is working on right now: http://blog.tojicode.com/2014/07/bringing-vr-to-chrome.html. Or it could be Firefox Nightly: https://nightly.mozilla.org/. Both require enabling a flag to turn WebVR on.
I say "officially", because I do have a system for using the browser's motion sensor APIs to control the view, but I had turned it off a while ago due to problems with the motion sensor APIs. The various browser vendors don't implement the Device Motion and Device Orientation APIs with the same origin or range of values. My code tries to compensate and renormalize it, but I don't have a wide range of devices on which to test. A WebVR-enabled browser will be more reliable and have smoother tracking. Without the WebVR API, the monkeying the browser does to the motion sensor data (none of them provide a raw stream, they all attempt to do a sensor fusion process, to varying degrees of non-success) makes for a jittery, drifty experience. It's enough that you might get motion sick if you haven't been using VR headsets for a while.
That said, I think most people are probably just browsing, so I've put the regular motion-controls back in this morning. It should work in most mobile browsers now.
Nightlies are Firefox's experimental browser (https://nightly.mozilla.org/). Basically updates get pushed 3x before they're finally released: Central (Nightly) > Aurora (Alpha stage) > Beta > Release (Firefox): I believe each one can be downloaded as a separate browser, rather than just switching your update channel (https://www.mozilla.org/en-US/firefox/channel/).. So in order to do that with Waterfox, you'd have to get the new source code and apply it into Waterfox's source code, then recompile Waterfox. All of which is doable, if you want to spend the time doing it just for that.
Hope I didn't misunderstand your question.
The videos you will have access to, by signing up to VRPornCinema.com, are traditional 2D, HD videos (and 3D coming soon!) that are compatible to watch with VR headsets, including gaze controls to select videos and change video settings. The vidoes are NOT 180° and 360° videos.
Mobile:
Android phones are supported. Requires a WebGL-compatible browser. The faster the phone the better. We recommend Google Cardboard V2-compatible headsets for best results. Tested with Chrome on Android.
GearVR is supported by bypassing the GearVR service; either by inserting your phone into the GearVR without plugging in the mini-USB, or by using Package Disabler to temporarily disable the GearVR service, preventing it from starting up when plugging your phone into the GearVR.
*iPhones are NOT currently supported. (iPhone support coming soon!) *
PC:
Oculus DK2 is supported
Windows is supported
For PC, Firefox Nightly with the WebVR add-on is required
- Install the latest Oculus runtime for windows.
- Install Firefox Nightly
- Install the VR add-on.
Macs are NOT currently supported. Unfortunately, Macs are not recommended for consuming content with the Oculus Rift. Oculus froze Mac and Linux SDK development in the summer of 2015, and while the 0.5.0.1 SDK is still currently available from their developer site, newer versions of OSX are beginning to break support for the Rift DK2. For actually consuming VR experiences, we recommend using Windows PCs or android mobile phones.
The videos you will have access to, by signing up to VRPornCinema.com, are traditional 2D, HD videos (and 3D coming soon!) that are compatible to watch with VR headsets, including gaze controls to select videos and change video settings. The vidoes are NOT 180° and 360° videos.
Mobile:
Android phones are supported. Requires a WebGL-compatible browser. The faster the phone the better. We recommend Google Cardboard V2-compatible headsets for best results. Tested with Chrome on Android.
GearVR is supported by bypassing the GearVR service; either by inserting your phone into the GearVR without plugging in the mini-USB, or by using Package Disabler to temporarily disable the GearVR service, preventing it frin starting up when plugging your phone into the GearVR
*iPhones are NOT currently supported. (iPhone support coming soon!) *
PC:
Oculus DK2 is supported
Windows is supported
For PC, Firefox Nightly with the WebVR add-on is required
- Install the latest Oculus runtime for windows.
- Install Firefox Nightly
- Install the VR add-on.
Macs are NOT currently supported. Unfortunately, Macs are not recommended for consuming content with the Oculus Rift. Oculus froze Mac and Linux SDK development in the summer of 2015, and while the 0.5.0.1 SDK is still currently available from their developer site, newer versions of OSX are beginning to break support for the Rift DK2. For actually consuming VR experiences, we recommend using Windows PCs or android mobile phones.
The videos you will have access to, by signing up to VRPornCinema.com, are traditional 2D, HD videos (and 3D coming soon!) that are compatible to watch with VR headsets, including gaze controls to select videos and change video settings. The vidoes are NOT 180° and 360° videos.
Mobile:
Android phones are supported. Requires a WebGL-compatible browser. The faster the phone the better. We recommend Google Cardboard V2-compatible headsets for best results. Tested with Chrome on Android.
GearVR is supported by bypassing the GearVR service; either by inserting your phone into the GearVR without plugging in the mini-USB, or by using Package Disabler to temporarily disable the GearVR service, preventing it frin starting up when plugging your phone into the GearVR
*iPhones are NOT currently supported. (iPhone support coming soon!) *
PC:
Oculus DK2 is supported
Windows is supported
For PC, Firefox Nightly with the WebVR add-on is required
- Install the latest Oculus runtime for windows.
- Install Firefox Nightly
- Install the VR add-on.
Macs are NOT currently supported. Unfortunately, Macs are not recommended for consuming content with the Oculus Rift. Oculus froze Mac and Linux SDK development in the summer of 2015, and while the 0.5.0.1 SDK is still currently available from their developer site, newer versions of OSX are beginning to break support for the Rift DK2. For actually consuming VR experiences, we recommend using Windows PCs or android mobile phones.
The videos you will have access to, by signing up to VRPornCinema.com, are traditional 2D, HD videos (and 3D coming soon!) that are compatible to watch with VR headsets, including gaze controls to select videos and change video settings. The vidoes are NOT 180° and 360° videos.
Mobile:
Android phones are supported. Requires a WebGL-compatible browser. The faster the phone the better. We recommend Google Cardboard V2-compatible headsets for best results. Tested with Chrome on Android.
GearVR is supported by bypassing the GearVR service; either by inserting your phone into the GearVR without plugging in the mini-USB, or by using Package Disabler to temporarily disable the GearVR service, preventing it frin starting up when plugging your phone into the GearVR
*iPhones are NOT currently supported. (iPhone support coming soon!) *
PC:
Oculus DK2 is supported
Windows is supported
For PC, Firefox Nightly with the WebVR add-on is required
- Install the latest Oculus runtime for windows.
- Install Firefox Nightly
- Install the VR add-on.
Macs are NOT currently supported. Unfortunately, Macs are not recommended for consuming content with the Oculus Rift. Oculus froze Mac and Linux SDK development in the summer of 2015, and while the 0.5.0.1 SDK is still currently available from their developer site, newer versions of OSX are beginning to break support for the Rift DK2. For actually consuming VR experiences, we recommend using Windows PCs or android mobile phones.
What I do is download the tar.gz, unzip it to my desktop, and move it to my /opt/ folder. (Make sure you give the entire /opt/firefox/ folder user write permissions! If you don't, Firefox won't update unless you run it as root.)
Then I make a launcher (I use the Mate desktop environment) with the /opt/firefox/firefox command and call it a day.
It does now, it's just not in release yet. Try the Nightly or DevEdition version of Firefox. You can click the icon to mute the tab. (And to your comment further down: Both of those versions also have multiprocess E10S enabled.)
Not sure about chrome, but firefox nightly recently (May) enabled support for OMTC and hardware acceleration. Grab a nightly build here and see if your issue is there too.
The Nightly and Beta versions are going to have bugs. So, at the end, you will end up having an inferior performance. I recommend staying on the stable release if you value speed and stability.
Nightlies with the latest features are here https://nightly.mozilla.org/
Like you latest Firefox release version has been disastrous for me too, so to bypass it I simply upgraded temporary to Nightly and it resolved the memory and lag issue of current version.
I loaded the latest nightly and it seems it isn't here, can only double tap to zoom one level.. which version? I downloaded it from here (armv7): https://nightly.mozilla.org/
edit: just saw the other comment.
I spoke with a dev person on IRC and they mentioned that they've been working on some flash specific issues. The fixes have been landed on Nightly. So if you'd be up to trying it out and letting me know if the problem still exists, I will pass it along if the problem persists (we may file a separate bug if it does).
I spoke with a dev person on IRC and they mentioned that they've been working on some flash specific issues. The fixes have been landed on Nightly. So if you'd be up to trying it out and letting me know if the problem still exists, I will pass it along if the problem persists (we may file a separate bug if it does).
I spoke with a dev person on IRC and they mentioned that they've been working on some flash specific issues. The fixes have been landed on Nightly. So if you'd be up to trying it out and letting me know if the problem still exists, I will pass it along if the problem persists (we may file a separate bug if it does).
It crashes when it gets to 4 because it's a 32-bit program, and 4GB is the limit for 32-bit programs. If Firefox would go 64-bit like Chrome, IE, and Safari, that'd be nice.
You may want to try downloading the 64-bit version of FF Nightly if it regularly gets to 4GB and crashes: https://nightly.mozilla.org/
I've been using the nightly build of Firefox and prefer it over Chrome. Stable version is on the play store and isn't much different.
- Install Firefox Nightly
- add new boolean in about:config (media.mediasource.ignore_codecs = true)
Note: You can have both stable and nightly installed at the same time. They will use separate directories. Nightly builds are slightly more buggy but the html5 & 1080p60 work fine on it.
Mozilla are working towards this at the moment with Electrolysis, which you can enable right now from Firefox 30 onwards. Buggy, and I wouldn't recommend it for the release channel, unless you want to move to Aurora or Nightly, but when your codebase is as old as Mozilla's, you've got to start somewhere!
The Nightly Builds fix some major bugs. However, it is suggested that people use it for testing purposes only (as there may be unexpected issues).