Examine source code of bookmarks-new-tab

{
  "manifest_version": 2,
  "name": "book-tabs",
  "version": "1.3",
  "applications": {
    "gecko": {
      "strict_min_version": "54.0"
    }
  },
  "chrome_url_overrides": {
    "newtab": "index.html"
  },
  "permissions": [
    "<all_urls>",
    "bookmarks"
  ],
  "description": "Replaces new tab page with a custom page which shows your bookmarks",
  "icons": {
    "48": "border-48.png"
  }
}