Each Calendar in your Keep&Share account has a Calendar name. Generally, when you are viewing a Calendar, the Calendar name will show up in the upper left-hand corner of your Calendar. This allows you to know which Calendar you are currently viewing.
When you are using Calendar Overlays you have the option of showing the title of the source Calendar that the Events in the Overlay came from. This option allows you to quickly identify which Events came from which Calendar. This is useful if you need to make any changes to the Events in the source Calendar. You can choose to do this for individual Calendar Overlays.
In the example below, you can see what your Calendar Overlays look like on your Calendar before adding the Overlay titles and after.