Examine source code of tabCast manager

{
  "name": "tabCast",
  "version": "0.1",
  "manifest_version": 2,
  "description": "Creates a WiFi Display Session from the 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
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{528a4023-06e1-43e2-b2cd-08148a53440e}"
    }
  }
}