The value of the accessibility element, in a localized string.
Mac Catalyst 13.0+
The default value for this property is nil unless the receiver is a UIKit control, in which case value of the property represents the value of the control, when it differs from the label.
When an accessibility element has a static label and a dynamic value, set this property to return the value. For example, although an accessibility element that represents a text field might have the label “Message,” its value is the text currently inside the text field.