I believe that I'm responsible for that. Jamie Turner asked me to review bump's STUD, which was at that point the "Scalable TLS something daemon"; I suggested

I believe that I'm responsible for that. Jamie Turner asked me to review bump's STUD, which was at that point the "Scalable TLS something daemon"; I suggested to him that the "something" could be "unwrapping" and would both make sense and make the acronym work. You'd have to ask Jamie to be sure, though. It's entirely possible that someone else suggested this too.