org-timestamp-split-range
org-timestamp-split-range is a compiled Lisp function in `org.el
'.
(org-timestamp-split-range TIMESTAMP &optional END)
Extract a timestamp object from a date or time range.
TIMESTAMP is a timestamp object. END, when non-nil, means extract
the end of the range. Otherwise, extract its start.
Return a new timestamp object sharing the same parent as
TIMESTAMP.