The first development release of Firefox 3, code name Gran Paradiso, is now available for testing, and against what I previously thought this release actually matters.

It happens that the main improvement here is not to the Firefox user interface or functionality but to the underlying Gecko rendering engine, responsible for proper presentation of web documents in Firefox, Thunderbird, NVU, Sunbird, Netscape, Flock and a number of other Gecko based products. Gecko 1.8.1 is what comes with Firefox 2.0 and the next major version will be Gecko 1.9 which is included in this alpha. It has been in development for more than one year now and developers want to test it as soon as possible since its a very large update.

Among these improvements is the inclusion of the new Cairo rendering engine. Until Firefox 2, it was used for rendering SVG images only. Its use has now been extended to handle full web page rendering. Among other benefits, Cairo provides a coherent output independently of the device, this means for example screen and print outputs will be the same, a welcome improvement for Firefox’s buggy printing abilities. Plus, the possibility to save web pages as PDF files. Additionally, Cairo can use the extra power provided by modern graphic accelerator cards for better performance.

Another set of improvements to CSS (a standard format language) support, allows Gran Paradiso to pass the Web Standards Project’s Acid2 test, which is nothing but a very complex HTML and CSS document that stresses a browser capabilities.
Acid2 test results before and after reflow branch landing are shown below:

MacOS X users will be pleased to learn the new Gecko uses Cocoa widgets instead of Carbon as featured in Firefox 2 and previous versions. Like in Camino, Cocoa widgets will provide a more natural feel in MacOS X environments.

Among minor user interface changes, accessing about:config, Firefox advanced configuration interface, users are prompted with a confirmation dialog.

Places, the integrated interface for bookmarks and history management is already being rolled in experimental builds and should be back to the main development trunk soon.

This alpha also marks the start of the end of support for Windows 95, 98 and Me versions. As previously announced, Firefox 3 won’t run on any of these versions.