Examine source code of Simple Weather Tracker

{
  "manifest_version": 2,
  "name": "Simple Weather Tracker",
  "version": "1.0",
  "description": "Check the current weather by entering your postal code.",
  "icons": {
    "48": "icon.png"
  },
  "permissions": [
    "storage",
    "activeTab"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{4df8e832-e628-41ea-b9be-221457432053}"
    }
  }
}