Firefox 3 alpha 7 has officially been released and is now available for download. The original tentative release schedule initially stated that the first beta would be released in late July, but the beta was delayed because of performance regressions. The alpha 7 release, which coincides with the Gecko 1.9 freeze, mostly includes backend improvements.

The most significant addition in alpha 7 is backend support for full-page zoom, which showed up in the nightly builds late last month. The alpha 7 release also includes support for SVG lighting and tile filters, redesigned XUL menus and tooltips, long-awaited color management support (still disabled by default), and support for cross-site XMLHttpRequest. Firefox 3 alpha 7 has some nice improvements that are specific to Mac OS X as well, including bug fixes for context menus and clipboard services.

There are also some changes to default options, most notably the length of time that the browser remembers page history. History retention has been extended from 9 days to 180 days. Some users may notice a considerable delay the first time they close Firefox 3 alpha 7 after upgrading since the history table gets rebuilt.

The next Firefox 3 pre-release, which is called Milestone 8, is scheduled for September 18. It isn't known yet whether or not Milestone 8 will be designated Firefox 3 alpha 8 or beta 1. According to the release schedule, Milestone 8 could potentially coincide with a front-end feature freeze. Like alpha 6, the alpha 7 release is a solid incremental improvement that reflects the tremendous amount of effort that has gone into improving Firefox under the hood.