Optionalpage1-based page the widget sits on (from its /P).
OptionalboundsWidget rectangle [x, y, width, height] in points, top-left origin
(already Y-flipped from the PDF's bottom-left /Rect).
OptionalexportFor a button widget, its on-state export name (the non-Off /AP /N key)
— which radio button this widget is / the value stored when selected. Absent
for text and choice widgets.
One on-page placement of a form field — a single widget annotation. See FieldInfo.widgets.