Thunar is a file manager for Linux and other Unix-like systems, written using the GTK+ 2 toolkit and shipped with Xfce version 4.4 RC1 and later. Thunar is developed by Benedikt Meurer, and was originally intended to replace XFFM, Xfce's previous file manager. Thunar was initially called Filer but was changed to Thunar due to a name clash.
The main goal of the Thunar project is to create a file manager that is fast, clean, and easy to use. It is designed to start up faster and be more responsive than other Linux file managers, such as Nautilus and Konqueror . Accessibility, another goal of the project, is accomplished using Assistive Technologies (i.e., GNOME Accessibility Toolkit). Like the rest of Xfce, Thunar is designed to comply with standards, such as those stated at freedesktop.org. Thunar is simple and lightweight by design, but its functionality can be extended through plugins.
The Thunar interface was developed prior to the coding of the Thunar core. First, a minimally functional software mock-up was built in Python. Features were added and UI elements were changed iteratively to react to test user input.
Thunar can also be extended by writing scripts to be placed in the context menu for various file types.