Sets one or more CSS classes to be applied to any value pattern text in the column header.
This text provides information to the user on the format of data to be entered for date/time columns e.g. hh:mm:ss, mm/dd/yyyy etc.
Multiple classes are specified by using a space between the class names, as per the HTML class parameter.
Further documentation.
These classes are configured in the studio using the Advanced Properties button within the Table Control Styling Assistant.