Mozilla has released the second alpha version of what will become its Firefox 3.0 browser. The release is the latest milestone in a plan to put the open-source browser in users' hands during the second half of the year.

Dubbed 'Gran Paradiso', the preview is still geared toward "web application developers and our testing community," according to release notes on the Mozilla site. The company warns more general users to steer clear and stick with the 2.0.x and 1.5.x production versions.

Among the changes to the second alpha are enhancements in how pages render incrementally, such as while images load or dynamic changes are made to a page; improvements in the browser's interaction with Mac OS X widgets; and full support for ACID2 test compliance.

Firefox 3.0, which is based on the new Gecko 1.9 layout engine, will be the first Mozilla browser to drop support for Windows 95, 98 and Millennium, as well as for Mac OS X 10.2 and earlier.

Alpha 2 can be downloaded in Windows, Mac OS X and Linux versions from the Mozilla website.