The border stroked around a cell: its line width and colour. A width of 0 draws no border.
public sealed record TableBorder : IEquatable<TableBorder>
ISO 32000-2 §14.8.5.4.2 (the BorderThickness and BorderColor layout attributes).
kind:method, kind:property, kind:ctor. Press Esc to clear.TableBorder(Double, Nullable<PdfColor>)A border width points wide in color (null for black).