What is the function of Exclude or Exclude Class related to the data or class?

Exclude (or Exclude Class) tag helps to control the set of choices, available in Flex Builder. But it never excludes the classes from linking. There is an MXML option that depends on how the application is been compiled. Generally, the classes that are included are those that are referenced from the root application or classes, either directly or via some other class that is referenced directly or not from the root application or classes.