calendar-frame-setup is an autoloaded Lisp function in `cal-x.el'.

(calendar-frame-setup CONFIG &optional PROMPT)

Display the calendar, and optionally the diary, in a separate frame.
CONFIG should be one of:
`calendar-only' - just the calendar, no diary
`one-frame' - calendar and diary in a single frame
`two-frames' - calendar and diary each in a separate frame

If CONFIG has any other value, or if the display is not capable of
multiple frames, then `calendar-basic-setup' is called.

If PROMPT is non-nil, prompt for the month and year to use.