Examine source code of Todolist Task

{
  "manifest_version": 3,
  "name": "Todolist",
  "version": "1.0",
  "description": "A simple todolist extension.",
  "icons": {
    "16": "icons/icon16.png",
    "32": "icons/icon32.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "action": {
    "default_popup": "popup/index.html"
  },
  "permissions": [
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "todolist@example.com"
    }
  }
}