Examine source code of ClickTracker

{
  "description": "Tracks the clicks performed in a webapp",
  "manifest_version": 2,
  "name": "ClickTracker",
  "version": "1.1",
  "icons": {
    "48": "./icons/tracker48.png",
    "96": "./icons/tracker96.png"
  },
  "permissions": [
    "activeTab",
    "notifications"
  ],
  "background": {
    "scripts": [
      "./backgroundScript/bgscript.js"
    ]
  },
  "browser_action": {
    "default_icon": "icons/tracker48.png",
    "default_title": "App Tracker",
    "default_popup": "./page/page.html"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "./contentScript/tracker.js"
      ]
    }
  ]
}