Examine source code of &udm=14

{
  "manifest_version": 2,
  "name": "&udm=14",
  "version": "2.9",
  "description": "Modifies Google Search URLs to include '&udm=14' when enabled.",
  "permissions": [
    "storage",
    "webRequest",
    "webRequestBlocking",
    "*://*.google.com/*",
    "*://*.google.co.uk/*",
    "*://*.google.de/*",
    "*://*.google.fr/*",
    "*://*.google.ca/*",
    "*://*.google.com.au/*",
    "*://*.google.co.in/*",
    "*://*.google.com.br/*",
    "*://*.google.ru/*",
    "*://*.google.co.jp/*",
    "*://*.google.com.mx/*",
    "*://*.google.it/*",
    "*://*.google.es/*",
    "*://*.google.nl/*",
    "*://*.google.co.za/*",
    "*://*.google.com.ar/*",
    "*://*.google.pl/*",
    "*://*.google.com.eg/*",
    "*://*.google.com.tr/*",
    "*://*.google.gr/*",
    "*://*.google.se/*",
    "*://*.google.ch/*",
    "*://*.google.com.hk/*",
    "*://*.google.co.kr/*",
    "*://*.google.sg/*",
    "*://*.google.ie/*",
    "*://*.google.co.il/*",
    "*://*.google.com.sa/*",
    "*://*.google.ae/*",
    "*://*.google.pt/*",
    "*://*.google.be/*",
    "*://*.google.no/*",
    "*://*.google.dk/*",
    "*://*.google.fi/*",
    "*://*.google.cz/*",
    "*://*.google.at/*",
    "*://*.google.co.nz/*",
    "*://*.google.cl/*",
    "*://*.google.com.co/*",
    "*://*.google.com.vn/*",
    "*://*.google.com.ng/*",
    "*://*.google.co.id/*",
    "*://*.google.hu/*",
    "*://*.google.ro/*",
    "*://*.google.com.ph/*",
    "*://*.google.bg/*",
    "*://*.google.sk/*",
    "*://*.google.hr/*",
    "*://*.google.com.my/*",
    "*://*.google.com.pk/*",
    "*://*.google.com.pe/*",
    "*://*.google.lk/*",
    "*://*.google.co.th/*",
    "*://*.google.kz/*",
    "*://*.google.by/*",
    "*://*.google.com.kh/*",
    "*://*.google.com.tn/*",
    "*://*.google.ge/*",
    "*://*.google.com.ua/*",
    "*://*.google.md/*",
    "*://*.google.az/*",
    "*://*.google.tm/*",
    "*://*.google.com.bd/*",
    "*://*.google.al/*",
    "*://*..google.mn/*",
    "*://*.google.am/*",
    "*://*.google.jo/*",
    "*://*.google.ps/*",
    "*://*.google.com.ly/*",
    "*://*.google.com.mt/*",
    "*://*.google.tt/*",
    "*://*.google.bs/*",
    "*://*.google.com.bh/*",
    "*://*.google.com.kw/*",
    "*://*.google.com.qa/*",
    "*://*.google.iq/*",
    "*://*.google.com.gh/*",
    "*://*.google.com.et/*",
    "*://*.google.co.ug/*",
    "*://*.google.mu/*",
    "*://*.google.com.af/*",
    "*://*.google.com.cy/*",
    "*://*.google.com.lb/*",
    "*://*.google.com.sv/*",
    "*://*.google.com.gt/*",
    "*://*.google.com.hn/*",
    "*://*.google.com.ni/*",
    "*://*.google.com.py/*",
    "*://*.google.com.bo/*",
    "*://*.google.com.do/*",
    "*://*.google.com.jm/*",
    "*://*.google.com.na/*",
    "*://*.google.com.zm/*",
    "*://*.google.co.zw/*",
    "*://*.google.com.bn/*",
    "*://*.google.la/*",
    "*://*.google.com.mm/*",
    "*://*.google.com.fj/*",
    "*://*.google.com.ws/*",
    "*://*.google.com.sb/*",
    "*://*.google.com.vc/*",
    "*://*.google.com.tz/*",
    "*://*.google.com.pg/*",
    "*://*.google.com.sl/*",
    "*://*.google.gp/*",
    "*://*.google.ga/*",
    "*://*.google.com.bi/*",
    "*://*.google.com.sz/*",
    "*://*.google.com.ki/*",
    "*://*.google.com.to/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_popup": "popup.html"
  },
  "icons": {
    "16": "logo16x16.png",
    "48": "logo48x48.png",
    "128": "logo.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "url-modifier@example.com",
      "strict_min_version": "58.0"
    }
  }
}