Firefox 41版刚发布没多久，现在，Mozilla又推出了42.0 beta版，主打隐私保护和追踪牌。这项叫做隐私浏览下的追踪保护(Tracking Protection in Private Browsing)的试验性功能将覆盖各大平台，包括Mac、Windows、Linux、Android。据悉，该功能主要针对第三方对用户使用习惯的追踪。
近期，开发商对这方面变得尤为重视。比如苹果最新发布的iOS 9，就具备了屏蔽第三方数据追踪的功能。
除了追踪保护功能之外，42.0 beta版Firefox还加入多个其他新的功能，如桌面客户端下的浏览器其控制中心(Control Center)现具备了安全与隐私控制功能、播放音频的标签得到了新的指示标记、一键静音功能、登录管理和WebRTS功能加强、加入更多类型HTML5和以开发者为方向的更新。
Android版（移动版）同样也有大量新增的功能如在后台打开Android软件的外部URL、无需切换软件就能打开多个链接、支持在地址栏中直接输入语音、允许用户预览、编辑及删除登录。
http://dm-download02.mozilla.org/pub/mozilla.org/mozilla.org/firefox/releases/42.0b7/
New
Private Browsing with Tracking Protection blocks certain Web elements that could be used to record your behavior across sites
New
Indicator added to tabs that play audio with one-click muting (Adobe Flash supported since version 19)
New
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 Windows Chrome and IE; import anytime from the Login Manager
New
Control Center that contains site security and privacy controls
New
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
HTML5
Implemented ES6 Reflect
HTML5
Support ImageBitmap and createImageBitmap()
HTML5
Media Source Extension for HTML5 video available for all sites
Developer
Remote website debugging over WiFi (no USB cable or ADB needed)
Developer
Asynchronous call stacks now allow web developers to follow the code flow through setTimeout, DOM event handlers, and Promise handlers.
Developer
Configurable Firefox OS Simulator in WebIDE, to simulate reference devices like phones, tablets, even TVs
Developer
CSS filter presets in the Inspector
Developer
Ability to save filter presets inside CSS Filter Tooltip
Developer
View HTML source in a tab