The main file manager window in Opus is called a "Lister".

 

The screenshot above shows a basic Lister with the default Opus configuration. It features three top toolbars, a folder tree on the left, and the file display on the right (with another toolbar above it.) The folder tree highlights the C: drive, whose contents are depicted to its right. Below the file display is the folder tab bar - currently, only one tab is open (the one showing C:) but you can open as many folders as you like each in their own tab, and rapidly switch between them.

Below that lies the status bar, offering a configurable summary of the contents of the folder.

While the Lister might appear similar to Windows File Explorer, Opus intentionally mirrors its design for initial user familiarity. Beneath the interface, Opus provides advanced functionality that users can gradually explore.

 

This screenshot illustrates a much more complex Lister, and immediately you can see that the resemblance to Explorer is only superficial. The key user interface elements visible in this screenshot are: