Examine source code of Popstar Online Html5

{
  "manifest_version": 2,
  "name": "Popstar Online Html5",
  "version": "1.0",
  "description": "Popstar Online is an interesting puzzle-like game. By selecting or dragging parts that share the same color",
  "permissions": [
    "activeTab"
  ],
  "browser_action": {
    "default_icon": {
      "128": "images/popstar.png"
    },
    "default_title": "Open Popup",
    "default_popup": "popup.html"
  },
  "icons": {
    "128": "images/popstar.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{62a99861-065f-45ff-9bc2-0fbb59021030}"
    }
  }
}