Examine source code of Simple New Tab

{
  "manifest_version": 2,
  "name": "Simple New Tab",
  "version": "1.5",
  "description": "A minimalistic, configurable new tab page.",
  "icons": {
    "16": "icon16.png",
    "32": "icon32.png",
    "48": "icon48.png",
    "64": "icon64.png",
    "128": "icon128.png",
    "256": "icon256.png",
    "512": "icon512.png"
  },
  "author": "cubedhuang",
  "chrome_url_overrides": {
    "newtab": "index.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{9e62c55d-a979-4e99-9cce-8ee030c11274}"
    }
  }
}