How do I know if a stranger has programmed you on WhatsApp?

This is a way to achieve which users you have not backed up that you have listed in their contact list.

To find out which stranger you have programmed, simply go to the WhatsApp main menu (the top three points on the right) and select the option "New Broadcast" to send a message to everyone who added you

When you enter this option, a list of contacts will be opened and those who are not registered in your agenda with the corresponding name will be the one you have programmed without you have it.