Examine source code of Keyword Alert

{
  "manifest_version": 2,
  "name": "Keyword Alert",
  "version": "1.0",
  "description": "Alerts users when specified keywords appear on a webpage.",
  "permissions": [
    "storage",
    "activeTab"
  ],
  "browser_action": {
    "default_popup": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{7c15aa25-6da7-4861-b427-8c57362f2151}"
    }
  }
}