Represents the "RO" entry of the redaction annotation object.

It is an optional entry defined as part of the PDF 1.0 specification.

It contains a FormXObjectElement.

For definitive details see:.

The ISO PDF Specification, ISO 32000-1:2008 PDF 1.7; Table: 192, page 413.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 195, page 501.

The rollover overlay form XObject is displayed on top of the annotation region when the pointer is over it, allowing an informational overlay before the redaction is applied.