Examine source code of Google Art Project

{
  "manifest_version": 2,
  "name": "Art Project - New Tab",
  "description": "display random masterpieces from Google Cultural Institute in your every new tab",
  "version": "0.1.6",
  "background": {
    "persistent": false,
    "scripts": [
      "background.js"
    ]
  },
  "chrome_url_overrides": {
    "newtab": "data/override/index.html"
  },
  "permissions": [
    "storage"
  ],
  "homepage_url": "https://add0n.com/new-tab.html?from=artworks",
  "icons": {
    "16": "data/icons/16.png",
    "24": "data/icons/24.png",
    "32": "data/icons/32.png",
    "48": "data/icons/48.png",
    "64": "data/icons/64.png",
    "128": "data/icons/128.png",
    "256": "data/icons/256.png"
  }
}