Examine source code of Document Scanning

{
  "name": "Document Scanning  ",
  "version": "3.1",
  "manifest_version": 2,
  "minimum_chrome_version": "37",
  "app": {
    "background": {
      "scripts": [
        "background.js"
      ]
    }
  },
  "permissions": [],
  "optional_permissions": [
    "documentScan"
  ]
}