Alpha 6 of Firefox 3.0, aka Gran Paradiso, includes an upgraded SQLite engine, the database that serves as the back-end storage house for Places - a new history and bookmark manager. Other Alpha 6 upgrades include improved cookie performance; support for site-specific preferences, such as text size; and enhancements of the add-on and download tools.

As usual, Mozilla waved off casual users. "Gran Paradiso Alpha 6 is intended for web developers and the Mozilla testing community only, with regular end users strongly advised to stick with the stable Firefox 2 for now," the company-hosted mozillaZine site said.

Mozilla plans to release the first public version of Firefox 3.0 Beta 1 on 31 July. According to the updated roll-out schedule, Beta 2 will appear in September, and the final release is due sometime before the end of the year.

In other Firefox news, Mozilla's upgrade offer to users of Version 1.5 has resulted in more than 3 million downloads of Firefox 2.0 since last Thursday. Upgrades topped out at around 30 per second, but have settled down at about 13 per second, Mozilla said.

Users are asked to choose whether to update to 2.0, delay the update or permanently reject it. Mozilla is trying to get all users to upgrade to the current browser because support for Firefox 1.5 ended in May. That same fate will befall Firefox 2.0 six months after Version 3.0 launches.

Alpha 6 can be downloaded for Windows, Mac OS X, and Linux at the Mozilla website.