Stores the per-item JSON payload for the current ItemType. field items require { "fieldName": string, "itemKey"?: string, "dateFormat"?: { "preset": string, "customFormat"?: string } }. heading items require { "headingText": string, "headingLevel": "h2"|"h3"|"h4"|"h5"|"h6", "css"?: string, "itemKey"?: string }. custom-html items require { "name": string, "html"?: string, "itemKey"?: string }. sub-wrapper items carry an empty JSON object ({}); all the sub-wrapper's data (name, preset, css, nested columns) rides on the sibling SubWrapper navigation property, and the linked ContentTemplateWrapper row's Id is round-tripped via Id on save (no itemKey needed for matching — the wrapper Id flow handles identity preservation).

The message to display to the client user about the outcome of the request

Whether the request is a 'Success' or 'Failure'

Status Code of the response