Adarna, Random Gradients and facts on new tab

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "manifest_version": 2,
  "name": "Adarna, Random Gradients and facts on new tab",
  "short_name": "Adarna",
  "version": "2.1.0",
  "description": "Fills up your new tab with color gradients from uigradients.com and displays random facts each time you open up a new tab.",
  "icons": {
    "128": "images/icon.png"
  },
  "browser_action": {
    "default_icon": "images/icon.png"
  },
  "background": {
    "scripts": [
      "js/background.js"
    ],
    "persistent": false
  },
  "permissions": [
    "tabs",
    "background"
  ],
  "chrome_url_overrides": {
    "newtab": "adarna.html"
  }
}