http://rox.sourceforge.net/phpwiki/

ROX is a fast, user friendly desktop which makes extensive use of drag-and-drop. The interface revolves around the file manager, or filer, following the traditional Unix view that `everything is a file' rather than trying to hide the filesystem beneath start menus, wizards, or druids. The aim is to make a system that is well designed and clearly presented. The ROX style favours using several small programs together instead of creating all-in-one mega-applications.

Knosciences specific mime-types works.