UML models can be large and complex, particularly in team environments
where the models are shared and edited by different people. To make it easier
to work with a large model, you can save portions of the model as fragments,
which are subunits of the model stored in separate files.
About this task
Each fragment is saved as an EFX file. Fragments can contain cross-references
to other fragments, and if they are no longer required, can be moved back
into the parent model.