It's what it says. It's apps you deleted that had used data. So it groups all the data from apps you have deleted during your current data cycle and shows the data usage for apps/users that are no longer installed.
T-Mobile 32GB - Rooted Wicked v5 (TWRP 18.104.22.168)
Galaxy Note 10.1 32GB 2014 Edition
Galaxy S4 (VZW MDK) sold to pay for my Note 3
Droid Bionic - Traded for Note 3
Droid X - Now a WiFi phone.