That's another 3rd party add-on. Presumably you will get it again in the same way that you got it in the first place. If you are unsure you should post in the ratings add-on discussion thread regarding this.
You should have received an email with a download link for it (it's using one of the services but it will be from DarkCart). Just do a search of your emails on the account that you registered it with using that term (DarkCart) and you should be able to click on the provided link. Otherwise, you will need to contact Luke to have him validate your license and resend you a link.