Mozilla.org released Firefox version 42.0 on Tuesday, and top of the new features is "Private Browsing with Tracking Protection." The browser specifically, "blocks certain Web elements that could be used to record your behavior across sites."
Firefox Private Browsing Mode with Tracking Protection Screenshot
In other words, Mozilla is making privacy even more of a selling point for its browser, something that Apple CEO Tim Cook has said would become more important to consumers as time went on. The feature also strikes a blow at Google, Facebook, and a host of third party ad networks that make tracking your every move on the Internet part of their business model.
The feature is being added to the Private Browsing mode that was already part of Firefox. Like Chrome's Incognito mode and Safari's Private Browsing mode, Firefox Private Browsing mode blocks cookies and Web history from being tracked. Tracking Protection specifically blocks third party trackers from doing their things, too.
Firefox version 42.0 also includes a Control Center for specifically controlling privacy and security settings. There's also an indicator for which tabs are playing sound (like Safari in OS X El Capitan), support for IPV6 and other WebRTC technologies, and more.
Other enhancements include new HTML5 support, changes to Firefox's Login Manager, a few bug fixes, and changes aimed at developers.
Firefox is a free download for Mac, Windows, and Android.