Examine source code of Masked Email Manager

{
  "manifest_version": 3,
  "name": "Masked Email Manager",
  "version": "1.7.2",
  "description": "A web extension to manage your Fastmail masked emails",
  "options_ui": {
    "page": "src/pages/options/index.html"
  },
  "action": {
    "default_popup": "src/pages/popup/index.html",
    "default_icon": "icon34.png"
  },
  "icons": {
    "34": "icon34.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "permissions": [
    "storage",
    "tabs"
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "contentStyle.css",
        "icon128.png",
        "icon34.png",
        "icon48.png"
      ],
      "matches": []
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{c48d361c-1173-11ee-be56-0242ac120002}"
    }
  }
}