Node:Read-only buffer, Next:b for interactive, Previous:insert-buffer interactive, Up:insert-buffer interactive
The asterisk is for the situation when the buffer is a read-only
buffer--a buffer that cannot be modified. If
called on a buffer that is read-only, a message to this effect is
printed in the echo area and the terminal may beep or blink at you;
you will not be permitted to insert anything into current buffer. The
asterisk does not need to be followed by a newline to separate it from
the next argument.