I know Android has a nice built-in way to visualize the monthly data usage on a daily basis. It also displays the cumulative data transfered data per app per cycle (1 month).
Where are the data usage numbers stored internally? And how detailed are they? More specifically, I am trying to figure out which app consumed data in the last X hours (or between timestamp A and timestamp B). Something ate up all remaining prepaid data last night (oddly while I was on WiFi and with background data restricted).