The Folder Alias system lets you assign aliases to folder paths that can then be used elsewhere in Opus. This lets you refer to long, complicated paths using a simple, easy to remember name. For example, instead of a function that reads Go C:\Users\My Name\Documents\Visual Studio Projects you could assign an alias to this folder, and replace the function with Go /projects.
Directory Opus also includes a large number of built-in aliases that refer to special system folders. For example, /desktop is an alias for the desktop folder, and /dopusdata is an alias for the main Opus configuration directory. These aliases can't be edited and by default are hidden from the list in Preferences, but you can display them by turning on the Show built-in aliases option at the bottom of this page.
Aliases can be used when defining toolbar icons, background images, you can type an alias into the Find-As-You-Type field or the location field to browse to that location - basically anywhere in Opus that you would ordinarily use a full pathname, you can use an alias.