allout-set-boundary-marker
allout-set-boundary-marker is a compiled Lisp function in `allout-widgets.el
'.
(allout-set-boundary-marker BOUNDARY POSITION &optional CURRENT-MARKER)
Set or create item widget BOUNDARY type marker at POSITION.
Optional CURRENT-MARKER is the marker currently being used for
the boundary, if any.
BOUNDARY type is either :from or :to, determining the marker insertion type.