Examine source code of Bangs for Google (With Cache)

{
  "manifest_version": 2,
  "name": "Bangs for Google (With Cache)",
  "version": "1.1",
  "icons": {
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "description": "Use DuckDuckGo Bangs in the Google Search",
  "homepage_url": "https://github.com/rpbritton/bangs-for-google-with-cache",
  "permissions": [
    "alarms",
    "webRequest",
    "webRequestBlocking",
    "https://duckduckgo.com/bang.js",
    "http://www.google.com/search*",
    "http://www.google.co.jp/search*",
    "http://www.google.co.uk/search*",
    "http://www.google.es/search*",
    "http://www.google.ca/search*",
    "http://www.google.de/search*",
    "http://www.google.it/search*",
    "http://www.google.fr/search*",
    "http://www.google.com.au/search*",
    "http://www.google.com.tw/search*",
    "http://www.google.nl/search*",
    "http://www.google.com.br/search*",
    "http://www.google.com.tr/search*",
    "http://www.google.be/search*",
    "http://www.google.com.gr/search*",
    "http://www.google.co.in/search*",
    "http://www.google.com.mx/search*",
    "http://www.google.dk/search*",
    "http://www.google.com.ar/search*",
    "http://www.google.ch/search*",
    "http://www.google.cl/search*",
    "http://www.google.at/search*",
    "http://www.google.co.kr/search*",
    "http://www.google.ie/search*",
    "http://www.google.com.co/search*",
    "http://www.google.pl/search*",
    "http://www.google.pt/search*",
    "http://www.google.com.pk/search*",
    "https://www.google.com/search*",
    "https://www.google.co.jp/search*",
    "https://www.google.co.uk/search*",
    "https://www.google.es/search*",
    "https://www.google.ca/search*",
    "https://www.google.de/search*",
    "https://www.google.it/search*",
    "https://www.google.fr/search*",
    "https://www.google.com.au/search*",
    "https://www.google.com.tw/search*",
    "https://www.google.nl/search*",
    "https://www.google.com.br/search*",
    "https://www.google.com.tr/search*",
    "https://www.google.be/search*",
    "https://www.google.com.gr/search*",
    "https://www.google.co.in/search*",
    "https://www.google.com.mx/search*",
    "https://www.google.dk/search*",
    "https://www.google.com.ar/search*",
    "https://www.google.ch/search*",
    "https://www.google.cl/search*",
    "https://www.google.at/search*",
    "https://www.google.co.kr/search*",
    "https://www.google.ie/search*",
    "https://www.google.com.co/search*",
    "https://www.google.pl/search*",
    "https://www.google.pt/search*",
    "https://www.google.com.pk/search*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "omnibox": {
    "keyword": "!"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{832fc9ac-eaec-4568-92e1-a55fe382eb1f}"
    }
  }
}