Parent major mode from which special major modes should inherit.
This mode runs the hook `special-mode-hook', as the final step
during initialization.
key binding
--- -------
SPC scroll-up-command
- negative-argument
0 .. 9 digit-argument
< beginning-of-buffer
> end-of-buffer
? describe-mode
g revert-buffer
h describe-mode
q quit-window
DEL scroll-down-command