Represents the "BE" entry of the square annotation object.

It is an optional entry defined as part of the PDF 1.5 specification.

It contains a BorderEffectElement.

For definitive details see:.

The ISO PDF Specification, ISO 32000-1:2008 PDF 1.7; Table: 177, page 402.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 180, page 487.

The border effect applies a cloud or other treatment to the rectangle border. The RD inset should be used to keep the effect within the annotation's total bounding box.