Dolphin is a file manager for KDE. It is the default file manager for the current version, KDE 4, and can be optionally installed on KDE 3. Although replaced as the default file manager for KDE 4, Konqueror is still the default web browser, and can be used as an alternative file manager for power users.
Under previous KDE versions, Konqueror had served both as the default file manager and web browser. However, for many years users have criticized that Konqueror was too complex for simple file navigation. As a response, the two functions were divided into two separate applications. Under KDE 4, Dolphin was streamlined for browsing files, while sharing as much code as possible with Konqueror. Konqueror continues to be developed primarily as a web browser.