Examine source code of Wheee

{
  "name": "Wheee",
  "version": "1.0.2resigned1",
  "description": "Lets you know when an audible tab is closed",
  "icons": {
    "16": "icon-16.png",
    "48": "icon-48.png",
    "128": "icon-128.png"
  },
  "background": {
    "persistent": true,
    "scripts": [
      "wheee.js"
    ]
  },
  "applications": {
    "gecko": {
      "id": "wheee@ponyfleisch.ch"
    }
  },
  "manifest_version": 2
}