Examine source code of Github Tree Structure

{
  "name": "Github Tree Structure",
  "version": "3.8",
  "description": "To view the changed files as tree structure in Github",
  "manifest_version": 2,
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "web_accessible_resources": [
    "css/*",
    "images/*"
  ],
  "icons": {
    "16": "images/folder_16.png",
    "32": "images/folder_32.png",
    "48": "images/folder_64.png",
    "128": "images/folder_128.png"
  },
  "permissions": [
    "<all_urls>",
    "webNavigation",
    "tabs"
  ]
}