rmail-default-file vs. (deleted) rmail-default-rmail-file

The current value for rmail-default-file is "~/xmail", but in
2009-01-22 rmail used rmail-default-rmail-file which was "~/XMAIL",
which was the default when using rmail-output.

I don't have strong preferences about this, but would it be possible
to change the value to "~/XMAIL"?  If not, I think this should be
mentioned in NEWS somewhere, maybe something like:

 ** The default output file for `rmail-output' has changed to
 "~/xmail".