Examine source code of NFP

{
  "manifest_version": 2,
  "name": "Porn Blocker",
  "version": "1.0",
  "description": "Blocks access to pornography sites when searched and redirects to a custom page.",
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "tabs",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "web_accessible_resources": [
    "index.html"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{395ecbda-9c12-4033-8b30-aace4877873a}"
    }
  }
}