This field allows the user to select a file from the file system. Text can be added before the selection or a static text element can be added to display above the selection box (a little more visually appealing).
Pressing 'Next' without a file selected show the following message:
Messages for the file field can be customized by creating a custom lang pack and overriding the following values (attribute values wrapped for readability):
If you wish to have a file field that can be used optionally, use the attribute allowEmptyValue="true" inside of the nested spec element:
Note: Mixing file fields with other fields that have text in front of them can lead to formatting (layout) issues. Placing these types of elements on different panels can provide a much better user experience.