Examine source code of Rotate Webpage

{
  "manifest_version": 2,
  "name": "Page Rotator",
  "version": "1.0",
  "description": "Rotate the current page using a control dial.",
  "permissions": [
    "activeTab"
  ],
  "icons": {
    "48": "icons/loading.png",
    "128": "icons/circular-economy.png"
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/loading.png",
      "48": "icons/circular-economy.png",
      "128": "icons/dial.png"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{5938b94d-03f0-47c2-83f1-e317ac8bf99f}"
    }
  }
}