Examine source code of Heavy rain icon

{
  "manifest_version": 2,
  "name": "Heavy rain icon",
  "version": "1.0",
  "description": "Heavy rain symbols are often depicted in a simple and recognizable style, especially in weather applications or meteorological maps.",
  "icons": {
    "48": "icon.png"
  },
  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html",
    "default_title": "Click me!"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{05a7f534-7757-4a7d-a0e1-9cb04b312814}"
    }
  }
}