Examine source code of Fortune Note

{
  "manifest_version": 2,
  "name": "FortuneNote",
  "version": "1.0",
  "description": "Add your own personalized fortune messages and view them on new tabs.",
  "icons": {
    "48": "icon.png"
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png"
  },
  "permissions": [
    "storage"
  ],
  "chrome_url_overrides": {
    "newtab": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{48cd5b4f-8d11-4ed6-8aa5-1b1f7166f269}"
    }
  }
}