What is the purpose of the Placeholder property in an Input widget?

The Placeholder property in an Input widget is designed to provide a hint or example about the expected input format or content for the user. This is particularly useful for guiding users on what information they should enter, such as specifying a date format (e.g., "DD/MM/YYYY") or indicating that a particular field requires an email address. The placeholder text appears inside the input field as a light gray prompt until the user starts typing, helping to improve the overall user experience by clarifying the expected form of input without cluttering the interface with static label instructions.

The other options address different functionalities. Specifying the input's data type is typically done through properties like 'Type' (e.g., text, number), indicating the current state of the input value relates to dynamic indicators such as validation states, and holding the validation message pertains to feedback provided after the user submits the form or if there is an error in the data entry. Each of these has its own distinct purpose in enhancing usability and providing necessary feedback but does not align with the function of the Placeholder property.