Examine source code of New Tab StartXXL

{
  "manifest_version": 2,
  "name": "StartXXL",
  "version": "3.0.3",
  "default_locale": "en",
  "description": "StartXXL extended Search and New Tab.",
  "icons": {
    "64": "icon.png"
  },
  "applications": {
    "gecko": {
      "id": "addon@startxxl.com"
    }
  },
  "permissions": [
    "activeTab",
    "tabs",
    "webNavigation",
    "webRequest"
  ],
  "chrome_url_overrides": {
    "newtab": "data/newtab.html"
  },
  "chrome_settings_overrides": {
    "homepage": "https://www.startxxl.com/",
    "search_provider": {
      "name": "StartXXL",
      "search_url": "https://www.startxxl.com/__MSG_searchQuery__{searchTerms}",
      "keyword": "www",
      "favicon_url": "https://www.startxxl.com/favicon.ico",
      "is_default": true
    }
  },
  "background": {
    "scripts": [
      "index.js"
    ]
  }
}