Examine source code of webhint

{
  "author": "webhint",
  "background" : {
    "scripts" : [
      "background-script.js" 
    ]
  },
  "icons" : {
    "180" : "icon.png"
  },
  "default_locale" : "en" ,
  "description" : "Quickly test your website to see if there are any issues with accessibility, browser compatibility, security, performance and more.",
  "devtools_page": "devtools/devtools.html",
  "manifest_version" : 2 ,
  "name" : "webhint",
  "permissions" : [
    "<all_urls>" ,
    "webNavigation" 
  ],
  "version" : "2.4.17",
  "browser_specific_settings": {
    "gecko": {
      "id": "{e748cb59-4901-4bea-b74a-1d8dab98e3c7}"
    }
  }
}