As Firefox 3 approaches its grand debut this next Tuesday, for Mozilla developers it means the end of a development cycle and the start of another. Firefox 3.next is the tentative name for the next relatively minor update to the Firefox 3 branch, which is most likely to become Firefox 3.1.

A very early draft of planned features reveals that as expected, this release will be mainly about landing stuff that didn’t make it on time for the Firefox 3, along with the usual performance, stability and security bug fixes.

Visual tab switching and tab searching/filtering were both tried for Firefox 3, abandoned for other more critical features, and are being considered for 3.1. Ctrl+Tab, a extension developed by Dao Gottwald implements both of them displaying a thumbnail of the opened tabs when pressing Ctrl + Tab to switch tabs.

It also modifies the List all tabs tab bar button to show tabs thumbnails you can search.

Ctrl+Tab, compatible with Firefox 3, is available at Mozilla Add-ons if you want to try these features.

Places would also receive several improvements like integrating the downloads history in the Library as it was planned for Firefox 3, so you could define smart folders of downloaded files. Regarding smart folders, the interface for advanced queries (like multiple criteria) that was available in the first betas and pulled back for performance concerns, would also come back.

Options for bulk tagging bookmarks and tag autocomplete are also being considered.

Add these to previously announced support for <video> tag, cross site Ajax requests, more power for the location bar, and some recently added support for CSS 3 selectors (which will improve Firefox score inthe Acid3 test), and we can already foresee an interesting update.

Following the tradition of using places as Firefox code names, Firefox 3.1 has been named Shiretoko after the Japanese national park.

Features in Firefox 3.1 should take about six weeks to implement with the rest of the time (the rest of the year) dedicated to polishing and testing. A first alpha is already targeted for mid July, just a month after Firefox 3.

Users are welcomed to join the discussion.