updated 01:26 pm EDT, Tue June 25, 2013
WebRTC toggled on by default
The Mac edition will now show download progress in the Dock app icon, and the Windows app now follows display scaling options for rendering bigger text on high-resolution displays. HTML5 additions include the ability to change audio/video playback speed, and support for "data" and "time" tags.
Mozilla says it has also improved WebGL rendering speed, and implemented several tools for developers, including CSS3 Flexbox, a Web Notifications API, and a built-in font inspector.