Examine source code of Time Spent

{
  "manifest_version": 2,
  "name": "Time Spent",
  "description": "This extension allow user to track time passed on every website",
  "version": "1.0.1",
  "author": "Jagjot Singh",
  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html"
  },
  "background": {
    "scripts": [
      "eventPage.js"
    ]
  },
  "permissions": [
    "activeTab",
    "https://ajax.googleapis.com/",
    "https://cdnjs.cloudflare.com/",
    "background",
    "tabs",
    "storage"
  ],
  "content_security_policy": "script-src 'self' 'unsafe-eval'; object-src 'self'",
  "browser_specific_settings": {
    "gecko": {
      "id": "{d7137094-9974-489d-8b2e-6bd623f788ef}"
    }
  }
}