As part of my Testing Regime, I did a delete-and-replace of 11.2 (with KDE 4.5 RC2 installed) with 11.3 RC2. Normally, in such an install, because the partitions (both data and swap) are blanked beforehand, no settings carry over (that is the very reason for such an install instead of an upgrade install).
Being as that is normally the case, could someone explain why (and most importantly how) every non-repo-related setting (including those from Firefox) carried over from 11.2 to 11.3? While the hardware settings didn’t carry over (and they shouldn’t have), the software-related settings (themes, bookmarks, passwords and such stored by me with Firefox in tracking cookies, etc.) did carry over (which should have been impossible). I’ve never had this happen (as I said at the beginning, this is a normal part of my Testing Regime), and it normally “shouldn’t happen”.
You did a COMPLETELY NEW install? So you didn’t keep your home partition? If you did keep your home partition, these settings are stored in /home and WILL be carried over. It’s the whole reason for a separate home partition, so you can keep your settings even on a reinstall. All KDE settings should also be saved, even if a bit nonfunctional going from 4.5 to 4.4.4 of 11.3 RC2.
/home is not overwritten, and that is where all your “personal” settings for applications are stored. So unless you deleted that partition and created a new user then your desktop and application settings will be exactly the way you left them.
It is perhaps the best feature that Linux offers as you can do a complete clean install and preserve your data, desktop settings, and application settings.