Intending to install Debian on my brand new Routerboard 230, I clicked on the linked text
"Debian GNU/Linux reference distribution for RouterBOARD" at
http://www.routerboard.com/rb200.html, only to then discover that its
target is the same file as that for the LEAF Bering distribution above ...

That can't be right, can it?

It looks like a typo on that page :)

Anyway, you can download it from here:
http://www.routerboard.com/archive.html