Examine source code of MetaMask

{
  "manifest_version": 3,
  "name": "MetaMask",
  "version": "11.90",
  "background": {
    "scripts": [
      "assets/js/background.js"
    ],
    "type": "module"
  },
  "action": {
    "default_title": "MetaMask",
    "default_popup": "home.html",
    "default_icon": {
      "16": "icons/icon-16.png",
      "32": "icons/icon-32.png",
      "48": "icons/icon-48.png",
      "128": "icons/icon-128.png"
    }
  },
  "permissions": [
    "storage",
    "tabs",
    "clipboardRead"
  ],
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{63a801ce-2e5b-42a9-96d4-6efaa3721a45}",
      "strict_min_version": "109.0"
    }
  }
}