{
  "type": "doc",
  "content": [
    {
      "type": "details",
      "attrs": { "open": false },
      "content": [
        { "type": "detailsSummary", "content": [{ "type": "text", "text": "Click to expand" }] },
        { "type": "detailsContent", "content": [
          { "type": "paragraph", "content": [{ "type": "text", "text": "Hidden body paragraph." }] }
        ]}
      ]
    }
  ]
}