Kubuntu is the first Ubuntu derived distribution. Our Kubuntu CDs are made up of Ubuntu's base plus KDE. You can get exactly the same effect by installing Ubuntu and adding the KDE packages (and removing the Gnome packages) from the Ubuntu archives.
There is no root password set as default. If KDE needs administrator privileges you should use your user password instead. You can also edit files as root from Konqueror with right click -> Actions -> Edit as Root. See the Root Sudo wiki page.
If you were using the standard Kubuntu desktop with KDE3, those settings will be migrated when you upgrade. Settings for the Kubuntu KDE4 Remix are not automatically migrated, but are preserved in your home directory so they can be manually moved from .kde4 to .kde.
Kubuntu comes with a simplified Konqueror profile to make things more use friendly compared to default KDE.
To get back to the default KDE profiles:
sudo rm -r /usr/share/kubuntu-default-settings/kde-profile/default/share/apps/konqueror
[this one not needed in gutsy] sudo cp /usr/share/apps/konqueror/konqueror-orig.rc /usr/share/apps/konqueror/konqueror.rc
To enable Konqueror to open tar and zip files:
sudo rm -r /usr/share/kubuntu-default-settings/kde-profile/default/share/mimelnk/application/
Yes, Kubuntu is Free software in the sense of freedom, so you can sell it on CDs or pre-installed on computers. You must however freely supply the source code if your customers ask for it, you can get source ISOs from
It means "towards humanity" in Bemba.
Coincidently it also means free (as in beer) in Kirundi, spoken in Burundi.
Kubuntu is pronounced "koo-boon-too".