Examine source code of Tab Open Chime

{
  "manifest_version": 2,
  "name": "Tab Open Chime",
  "version": "1.0",
  "description": "Play a short random chime when a new tab is opened.",
  "permissions": [
    "tabs"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "icons": {
    "48": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{b37d6807-9594-48c1-b4cf-5b0d71d8025c}"
    }
  }
}