Examine source code of Tab Statistics

{
  "name" : "Tab Statistics",
  "description" : "Statistics for tab count, opened, closed and switched for a given day.",
  "manifest_version" : 2 ,
  "version" : "2.0.3",
  "background" : {
    "scripts" : [
      "background.js" 
    ]
  },
  "browser_action" : {
    "default_title" : "Tab statistics not yet initialized",
    "default_icon" : {
      "16" : "icon.png",
      "32" : "icon.png",
      "48" : "icon.png",
      "96" : "icon.png"
    }
  },
  "permissions" : [
    "downloads" ,
    "storage" 
  ]
}