Mozilla releases Firefox 3 Alpha 6 - low key launch... but according to the Alpha 6 release notes this version includes:
Updated SQLite engine to version 3.3.17;
Support for site-specific preferences--text size;
A new Quit dialog box that resolves termination errors;
Added permanent 'Restart Firefox' button to Add-Ons Manager;
Miscellaneous fixes to download manager including correctly displaying large file sizes; various Places fixes;
and miscellaneous Gecko 1.9 bug fixes.