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Firefox Developer Edition
Release Notes

Release Notes tell you what’s new in Firefox. As always, we welcome your feedback. You can also file a bug in Bugzilla or see the system requirements of this release.

Firefox Developer Edition

August 14, 2015

Version 42.0a2, first offered to Firefox Developer Edition channel users on August 14, 2015


  • Improved private browsing windows block some web page elements that could track your web behavior across sites

  • Control Center that contains site security and privacy controls

  • Indicator added to tabs that play audio with one-click muting

  • GTK3 integration (GNU/Linux only)

  • Hardware acceleration for 2D canvas content (Mac OS X only)

  • Process separation enabled by default in Developer Edition

  • Login Manager improvements:

    • Improved heuristics to save usernames and passwords
    • Edit and show all logins in line, Copy/Paste usernames/passwords from the Context menu
    • Migration imports your passwords to Firefox from Google Chrome for Windows and Internet Explorer; import anytime from the Login Manager
  • WebRTC improvements:

    • IPV6 support
    • Preferences for controlling ICE candidate generation and IP exposure
    • Hooks for extensions to allow/deny createOffer/Answer
    • Improved ability for applications to monitor and control which devices are used in getUserMedia


  • Improved performance on interactive websites that trigger a lot of restyles


Web Platform


  • The CTRL+K shortcut does not give focus to the search field when used from the URL bar on GNU/Linux with GTK+ 3.14 and 3.16 (1176929)

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