Examine source code of Javascript Firewall

{
  "manifest_version" : 2 ,
  "name" : "Javascript Firewall",
  "version" : "1.4",
  "description" : "Block JavaScript of unwanted origin.",
  "browser_specific_settings": {
    "gecko": {
      "id": "javascript_firewall@example.com"
    }
  },
  "icons" : {
    "48" : "icons/icon.svg",
    "96" : "icons/icon.svg"
  },
  "permissions" : [
    "storage" ,
    "webRequest" ,
    "webRequestBlocking" ,
    "webNavigation" ,
    "*://*/*" 
  ],
  "browser_action" : {
    "default_icon" : "icons/icon.svg",
    "default_popup" : "popup.html"
  },
  "background" : {
    "scripts" : [
      "background.js" 
    ]
  },
  "options_ui" : {
    "page": "options.html" 
  }
}