Where an annotation's border was read from.
public enum PdfBorderSource
ISO 32000-2 §12.5.4 and §12.5.2, Table 166: BS wins over Border; with neither, the default applies.
kind:method, kind:property, kind:ctor. Press Esc to clear.BorderArrayThe Border array (Table 166).BorderStyleThe border style dictionary BS (Table 168).DefaultNeither entry is present: solid, 1 point, square corners (§12.5.4).