FindDuplicates plug-in does not only allow to see the potential duplicates while user creates new issue, but also automatically shows potential duplicates when user creates the links between issues.
This helps the user to save time as he/she does not have to do a manual search before linking the related tickets.
To see the potential list of duplicates linking the issues follow the steps:
By default, the list of potential duplicates contains 5 items. This setting can be changed by JIRA admin in FundDuplicates Configuration > General.