(defcustom temp-buffer-max-height (lambda (buffer) (/ (- (frame-height) 2) 2))
"Maximum height of a window displaying a temporary buffer.
-This is the maximum height (in text lines) which `resize-temp-buffer-window'
+This is effective only when Temp Buffer Resize mode is enabled.
+The value is the maximum height (in lines) which `resize-temp-buffer-window'
will give to a window displaying a temporary buffer.
-It can also be a function which will be called with the object corresponding
-to the buffer to be displayed as argument and should return an integer
-positive number."
+It can also be a function to be called to choose the height for such a buffer.
+It gets one argumemt, the buffer, and should return a positive integer."
:type '(choice integer function)
:group 'help
:version "20.4")