MyBB has a great referrals system, but it is not that well integrated into Profiles. MyBB default profile shows that a member has referred X users, but it's not possible to see who referred a particular user.

With WhoRefer? you can go to a users profile and see a clickable link to the user who referred them. If they did not select a referral on signup then the field says Nobody and is of course not clickable.

WhoRefer has language files so you can edit the Nobody text to your preferred variant

Check out the screenshot

AVAILABLE TRANSLATIONS
Persian by Parsian™