org-outline-overlay-data
org-outline-overlay-data is a compiled Lisp function in `org.el
'.
(org-outline-overlay-data &optional USE-MARKERS)
Return a list of the locations of all outline overlays.
These are overlays with the `invisible' property value `outline'.
The return value is a list of cons cells, with start and stop
positions for each overlay.
If USE-MARKERS is set, return the positions as markers.