Which editor(s) can open a UWAD?

I've always thought there was only IWADs and PWADs until today when I found a WAD file with a UWAD signature when I opened it in a hex editor. I tried to open it with Slade and XWE but that didn't work. Anyone have any experience with UWADs and know of a editor that can handle them?

Don't know that I've ever encountered a UWAD, where did you find yours?

In this zip file:
ftp://ftp.atari.com/patches/dzone/d-up13.zip

It looks like some kind of binary diff that gets read & applied by upgrade.exe, in order to upgrade someone's copy of "D!"

Anyway, seems like "D!" is some kind of front-end, because there's a /idgames/utils/frontends/d-up15.zip file (on /idgames mirrors).

<ninja'd by hex11>

Now I recognize it. That's not a Doom wad, it's an update patch for the "D!" frontend on the earlier D!Zone CDs.

Okay, thanks for solving that mystery :) I got tricked by the .WAD extension.