It's the DAZ Install Manager (DIM); it installs DAZStudio Content and retains installation paths for easy removal from the DS library. The DS files need to be packaged with a specific subfolder hierarchy, with the topmost folder entitled "Content." When you use DIM, the app strips out all the subfolders from within the "Content" folder and places them into the library. Again, all the subfolders need to be named accordingly to match the DS Library.

There was a small program developed to create DIM-compatible files, and it was available for free. It was called DIM-Maker-V0.4. I don't know if it is available anywhere; perhaps the Waybackmachine has a copy in its archives. I do know DAZ3D offered a DIM Maker in their store.