Examine source code of Tabbber

{
  "manifest_version": 2,
  "short_name": "Tab 3",
  "name": "Tabbber",
  "description": "Be more productive! Add your websites and search faster!",
  "version": "1.0.1",
  "author": "Aspiiire",
  "icons": {
    "16": "16.png",
    "48": "48.png",
    "128": "128.png"
  },
  "chrome_url_overrides": {
    "newtab": "index.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{14746ead-8442-4dda-bcf6-40589233d94d}"
    }
  }
}