Examine source code of MP3 Converter

{
  "manifest_version": 2,
  "name": "MP3 Converter",
  "version": "1.0",
  "description": "Easily convert and download video & audio files to .mp3 format.",
  "icons": {
    "48": "icon.png"
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "48": "icon.png"
    }
  },
  "permissions": [
    "downloads"
  ],
  "background": {
    "scripts": [
      "popup.js"
    ],
    "persistent": false
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{cceb4ffc-ab68-4aee-8c4e-8a6f8b9e6d73}"
    }
  }
}