I have been using android for a long time now like most of us here. I am presently using a AndroidOne phone. Sadly this phone has only 4 GB internal out of which roughly 2.5 GB is available for apps. After updating to Lollipop 5.1, I had to face the uphill task of maintaining the already severely low internal storage. So I started cleaning app caches, cleaning data and stuff. However I would really appreciate if some one will explain the App Info from Android Settings to me. In the storage section, Total and App are pretty clear and straight forward. What are USB Storage app, Data and SD Card.? And most importantly on what storage is this Data stored? I have attached an example screenshot. That specific app in on the SD card. Can someone please guide me with this?