Examine source code of Quick Speed Test

{
  "manifest_version": 2,
  "name": "Quick Speed Test",
  "version": "1.0.0",
  "description": "A simple Firefox add-on to estimate your internet download speed with a modern UI and history feature.",
  "icons": {
    "32": "speedtest-icon.png"
  },
  "browser_action": {
    "default_popup": "speedtest-ui.html",
    "default_title": "Quick Speed Test"
  },
  "permissions": [
    "storage",
    "https://picsum.photos/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{303ada5b-5742-42ea-bd70-f4a242293051}"
    }
  }
}