Q. In plain english, what is UDT?

UDT is a new type of file that holds a tree of information. UDT very similar to a zip file. Zip files can have files and folders inside of them. UDT can also, but it allows programmers to do much more elaborate things. For the average user, all you need to worry about is getting the UDT file viewer and editor, much like how you get WinZip to read zip files. Also, you only need this program if you care about editing or reading UDT files by hand. If your favorite program is using UDT files and it is doing what you want, then you can safely ignore this whole thing.