Firefox 3.1's beta 2 has arrived from Mozilla – with private browsing the biggest arrival for the increasingly popular browser.

The first beta for Firefox 3.1 arrived in October, brought improvements to the Gecko rendering engine and CSS 2.1 / 3 support .

The second beta has introduced the eagerly awaited TraceMonkey, a faster JavaScript engine as well as incorporating a number of other web standards.

Private

The headline act is, of course, private browsing - which has also been present in the latest iterations of rival browsers.

Private browsing allows users to choose for their history, cache and cookies from any given session to be deleted when the browser closes.

Mozilla suggests that this is 'ideal for Christmas shopping' with present shopping, of course, the primary reason that private browsing is popular.

Mozilla has also changed some of the tab behaviour – after changes in the last beta proved to be unpopular.

The beta is available now in 54 languages and for Windows, Mac OSX and Linux.