Examine source code of BNP Windows

{
  "name": "Merge Windows",
  "version": "1.0.2",
  "description": "Merges all of the browser's windows into the current window",
  "icons": {
    "48": "48.png",
    "128": "128.png"
  },
  "background": {
    "persistent": false,
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": "16.png",
    "default_title": "Merge Windows"
  },
  "manifest_version": 2
}