Examine source code of Mood Tracker

{
  "manifest_version": 2,
  "name": "Mood Tracker",
  "version": "1.0",
  "description": "Track your mood throughout the day.",
  "icons": {
    "48": "icons/mood-icon-48.png"
  },
  "permissions": [
    "storage"
  ],
  "browser_action": {
    "default_icon": "icons/mood-icon-48.png",
    "default_popup": "popup.html",
    "default_title": "Mood Tracker"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{2be5a69c-59f2-46a3-b2cb-3a676be6cb99}"
    }
  }
}