Konqueror is KDE's Webbrowser and swiss-army-knife for any kind of file-management and file previewing.
Features:
- Webbrowsing using KHTML or KDEWebKit as rendering engines
- File management using most of Dolphin's features (including version-control, service menus and the basic UI)
- File management on ftp and sftp servers
- Full featured FTP-client (you can split views to display local and remote folders and previews in the same window)
- Embedded applications to preview files (e.g. Okular and Calligra for documents, Gwenview for pictures, KTextEditor for text-files)
- Different kinds of plugins: Service-menus, KParts (embedded applications), KIO (accessing files using special protocols like http or ftp) and KPart-plugins (like AdBlocker...)