Examine source code of tabCast beast

{
  "name": "tabCast beast",
  "version": "1.2",
  "manifest_version": 2,
  "description": "It Creates a WiFi Display Session and captured tab media stream using chrome.displaySource API.",
  "permissions": [
    "tabCapture",
    "tabs",
    "displaySource"
  ],
  "browser_action": {
    "default_title": "Tab cast",
    "default_popup": "main.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  }
}