LayoutServiceResponse.json

{
  ...
  "placeholders": {
    "discovering-sitecore10-main": [
      {
        ...
        "fields": {
          "items": [
            {
              "id": "5603c106-09d8-4895-8aee-0ecfb3b69522",
              "name": "Children1",
              "displayName": "Children1",
              "fields": {
                "Title": {
                  "value": "I am the first children"
                }
              }
            },
            {
              "id": "763f460b-5e60-481f-9ea9-56bf34d8ae27",
              "name": "Children2",
              "displayName": "Children2",
              "fields": {
                "Title": {
                  "value": "I am the second children"
                }
              }
            }
          ]
        }
      }
    ]
  }
}