WDFUSE stands for Windows Dark Forces Utility and Editor. It is a Delphi written mission editor created by Yves Borckmans , a programmer from Belgium in 1995. Here is the story of how he created the Windows version of DFUSE in 1996
"Around 1995, when the Dark Forces DEMO came out, I started working on DFUSE (the DOS version, in C). I didn't release it then because it would have been a bit unethical (you could have made levels for the demo, never buying the game). When the full game came out, I did a few quick changes that were necessary (some formats changed slightly), then released DFUSE 1.0 on ftp.cdrom.com This included the first DF specs if I remember correctly. I made a couple of updates if I remember correctly, but nothing much. Later in that year, I also sent a copy of my C code to Brad Oliver, to help him start on the Mac editor (Dark Forge IIRC). Around 1996, I had to learn Delphi for work, so I decided the best way to learn was to use it to make a Windows version of DFUSE, and in a couple of weekends that became WDFUSE 1.0 I released a couple versions, then started preparing to move from Europe to the US to work at LucasArts. I enrolled the help of David Lovejoy, Alexei Novikov and Jereth Kok to help as I was working 2 jobs (my job + LucasArts) + preparing a transatlantic move lol We called ourselves The Code Alliance and they pretty much took over WDFUSE... many other people helped too! "
The editor was very popular in the editing community, even making it to various magazines such as this blurb from PC Zone magazine from August 1995 (page 118).