Examine source code of Customizable Scrollbars

{
  "manifest_version": 2,
  "name": "Customizable Scrollbars",
  "version": "1.0",
  "description": "Allows users to customize scrollbars on web pages.",
  "permissions": [
    "storage",
    "activeTab"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "Customize Scrollbars"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_end"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{14f97e40-b3fc-4ef2-a451-306e7b00dd2b}"
    }
  }
}