Examine source code of Track time on live

{
  "manifest_version": 2,
  "name": "Browser Time Tracker",
  "version": "1.0",
  "description": "Tracks how much time you spend in your browser and provides daily and weekly summaries.",
  "permissions": [
    "storage",
    "tabs"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_popup": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{2d083837-1dd7-4b9b-9dfa-b16dd1ae8d3e}"
    }
  }
}