discourse/spec/requests/api/schemas/json/post_update_request.json

{
  "additionalProperties": false,
  "properties": {
    "post": {
      "type": "object",
      "additionalProperties": false,
      "properties": {
        "raw": {
          "type": "string"
        },
        "edit_reason": {
          "type": "string"
        }
      },
      "required": ["raw"]
    }
  }
}