When a file is finally to your satisfaction, you can select to approve the file in Cage. By clicking the "MARK AS APPROVED" button, an approved stamp will be placed on the file which will denote who approved it and when. An email notification will also be sent so that everyone can celebrate.
If you mark this as approved on accident, you can "UNAPPROVE" the file (cause accidents do happen). However, chances are the designer(s) responsible are already doing a celebration dance.