+With a prefix argument ARG, enable View mode if ARG is positive,
+and disable it otherwise. If called from Lisp, enable View mode
+if ARG is omitted or nil.
+
+When View mode is enabled, commands that do not change the buffer
+contents are available as usual. Kill commands insert text in
+kill buffers but do not delete. Most other commands beep and
+tell the user that the buffer is read-only.