Examine source code of Travel card icon

{
  "manifest_version": 2,
  "name": "Travel card icon",
  "version": "1.0",
  "description": "The travel card icon is used to represent travel discount cards, airline tickets, travel membership cards, or services related to travel and travel experiences.",
  "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": "{389f6b95-6e2d-4cad-902e-e413d99f5267}"
    }
  }
}