with-help-window

with-help-window is a Lisp macro in `help.el'.

(with-help-window BUFFER-NAME &rest BODY)

Display buffer named BUFFER-NAME in a help window.
Evaluate the forms in BODY with standard output bound to a buffer
called BUFFER-NAME (creating it if it does not exist), put that
buffer in `help-mode', display the buffer in a window (see
`with-temp-buffer-window' for details) and issue a message how to
deal with that "help" window when it's no more needed. Select
the help window if the current value of the user option
`help-window-select' says so. Return last value in BODY.