Examine source code of Internet Speed Test

{
  "manifest_version": 2,
  "name": "Internet Speed Test",
  "version": "1.0",
  "description": "Quickly test your internet speed! Click to open a pop-up with buttons to launch Fast.com, Speedtest.net, or Google Speed Test in a new tab.",
  "permissions": [],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png"
  },
  "icons": {
    "48": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{5b4e9994-cfb6-4577-bdff-be33e701ab67}"
    }
  }
}