(@pxref{Formatting Variables}).
There should always be a colon on the line; the cursor always moves to
-the colon after performing an operation.
+the colon after performing an operation. (Of course, Gnus wouldn't be
+Gnus if it wasn't possible to change this. Just write a new function
+@code{gnus-goto-colon} which does whatever you like with the cursor.)
The default string is @samp{%U%R%z%I%(%[%4L: %-20,20n%]%) %s\n}.