custom-buffer-create is an autoloaded compiled Lisp function in `cus-edit.el'.

(custom-buffer-create OPTIONS &optional NAME DESCRIPTION)

Create a buffer containing OPTIONS.
Optional NAME is the name of the buffer.
OPTIONS should be an alist of the form ((SYMBOL WIDGET)...), where
SYMBOL is a customization option, and WIDGET is a widget for editing
that option.
DESCRIPTION is unused.