freshnessProperty property
This property indicates the freshness level of the object in the index.
If set, this property must be a top-level property within the property definitions and it must be a timestamp type or date type. Otherwise, the Indexing API uses updateTime as the freshness indicator. The maximum length is 256 characters. When a property is used to calculate freshness, the value defaults to 2 years from the current time.
Implementation
core.String? freshnessProperty;