Examine source code of Falling snow icon

{
  "manifest_version": 2,
  "name": "Falling snow icon",
  "version": "1.0",
  "description": "Snowfall icons are commonly used in weather apps, climate maps, winter graphic designs, and have a distinctive, easily recognizable image.",
  "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": "{719f27cb-83e5-4f75-a398-075e02db220a}"
    }
  }
}