That was part of a massive (free) Mac software conquest back in 2009. I was finally able to upgrade my parents' SE SuperDrive from System 6 with that software package (I never bothered installing At Ease as I didn't have a use for it; the disks are still sealed in their original shrink-wrap).
Interesting info regarding the LC520. Perhaps we should begin a thread (or a wiki) dedicated solely to packing lists. It would be a great reference.