Clicking that button opens a dialog that allows adding a range of times of day (hours and minutes) to a day. You pick:
- start time (of the time range),
- end time (of the time range),
- length (of the appointment), and
- period (for the time suggestions),
and the code computes the list of suggested times for you.
Note: This feature was developed and tested against the
v1.1.x stable branch. It should probably be forward-ported to
develop, which, as far as I can tell, does not yet have this feature either. But for now, I am submitting what I have so that you are aware of its existence.