org-icalendar-combine-agenda-files
org-icalendar-combine-agenda-files is an interactive autoloaded Lisp function in `ox-icalendar.el
'.
(org-icalendar-combine-agenda-files &optional ASYNC)
Combine all agenda files into a single iCalendar file.
A non-nil optional argument ASYNC means the process should happen
asynchronously. The resulting file should be accessible through
the `org-export-stack' interface.
The file is stored under the name chosen in
`org-icalendar-combined-agenda-file'.