Examine source code of r/a/dio

{
  "manifest_version": 2,
  "name": "Radio Stream Player",
  "version": "1.5",
  "description": "Plays and stops a radio stream",
  "permissions": [
    "activeTab"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icon.png",
      "32": "icon.png",
      "48": "icon.png",
      "128": "icon.png"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{e2c8cc6a-016a-4b1f-846a-e8ae64a4e7d9}"
    }
  }
}