Examine source code of Pretty New Tab Image

{
  "manifest_version": 2,
  "name": "Pretty New Tab (using Bing Images)",
  "version": "0.2resigned1",
  "chrome_url_overrides": {
    "newtab": "newtabpage.html"
  },
  "permissions": [
    "*://az619822.vo.msecnd.net/*",
    "webRequest"
  ],
  "applications": {
    "gecko": {
      "strict_min_version": "54.0a1",
      "id": "{3e6adfe4-2ff7-44dd-b79a-6bd874f66082}"
    }
  }
}