Examine source code of Simple Music Player

{
  "manifest_version": 2,
  "name": "Simple Music Player",
  "version": "1.0",
  "description": "Plays a specific music track when you click the button.",
  "icons": {
    "48": "icon.png"
  },
  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{93bfe53b-2272-4085-9e99-de02d0c2acde}"
    }
  }
}