Examine source code of Holiday Extension

{
  "manifest_version": 2,
  "name": "Holiday Extension",
  "description": "Change your Search Engine Background to a Holiday photo",
  "homepage_url": "https://www.holidayextension.com/",
  "background": {
    "scripts": [
      "js/background.js"
    ],
    "persistent": false
  },
  "permissions": [
    "storage",
    "https://www.bensendigital.com/holiday/",
    "https://*.bing.com/*",
    "https://search.yahoo.com/*"
  ],
  "version": "1.2",
  "browser_action": {
    "default_icon": {
      "16": "images/bd-16.png",
      "32": "images/bd-32.png",
      "48": "images/bd-48.png",
      "128": "images/bd-128.png"
    }
  },
  "icons": {
    "16": "images/bd-16.png",
    "32": "images/bd-32.png",
    "48": "images/bd-48.png",
    "128": "images/bd-128.png"
  },
  "chrome_url_overrides": {
    "newtab": "landing.html"
  },
  "externally_connectable": {
    "matches": [
      "https://www.holidayextension.com/*"
    ]
  }
}