Examine source code of StressMyPage

{
  "manifest_version": 3,
  "name": "StressMyPage",
  "description": "Stress test your web pages.",
  "version": "1.0.1",
  "browser_specific_settings": {
    "gecko": {
      "id": "stressmypage@exfabrica.com"
    }
  },
  "icons": {
    "16": "images/icon-16.png",
    "32": "images/icon-32.png",
    "48": "images/icon-48.png",
    "128": "images/icon-128.png"
  },
  "action": {
    "default_popup": "/popup/popup.html"
  },
  "background": {
    "service_worker": "/popup/background.js",
    "scripts": [
      "/popup/background.js"
    ]
  },
  "permissions": [
    "scripting",
    "activeTab",
    "storage",
    "webNavigation"
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "images/focus-image.png"
      ],
      "matches": [
        "<all_urls>"
      ]
    }
  ]
}