This option allows you to create a copy of an existing audience definition. The button is only enabled when an Unchanged audience definition is selected.
On invocation, the copy is created and selected automatically. All properties are per the original definition (however, if you clone the default definition, the newly-created clone is not marked as default).
The orange ‘The database will be validated…’ message is shown at the top of the Audience Definitions configuration interface, and a Validate audience definitions job is created and executed on subsequent invocation of Save.