Examine source code of Semantic new tab

{
  "manifest_version": 2,
  "name": "Semantic new tab",
  "version": "0.1.5",
  "author": "Daniil Egortsev",
  "chrome_url_overrides": {
    "newtab": "index.html"
  },
  "description": "New tab extension for Firefox built with React, Semantic UI and ❤️",
  "permissions": [
    "bookmarks",
    "storage"
  ],
  "background": {
    "scripts": [
      "main.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{4008220f-c682-44db-aa7d-78968d453217}"
    }
  }
}