Great question. Looking at the examples in the screenshot, it looks like it's an indicator as to where the contact is stored. For example, the DIGITS app may be reading the second number as one that's stored to your phones memory. This is just a guess, but I thinking you probably don't have that top number saved as a contact anywhere. Side note: I've noticed a sim card icon that shows up next to my contacts which makes sense to me since I know these contacts are stored there.
This thread was the product of our fantastic collaborators during DIGITS Beta! As many terms have changed and bugs have been exterminated since the Beta launched, the information here may no longer be accurate. If you still have a question, please search our active threads or ask a new question in the DIGITS space!