Fringes are 3d models (curves) but to keep the optimization on a high level, there are about 12 uniqe fringes (instead of over 120) and the rest are just instances (mirrored and rotated) so they share the same geometry and don't take that much space.

Yes, all models are marked as assets and can be easily used within your Asset Browser - just drag & drop it to your scene! Remember to set a File Path in your Asset Library first - you'll find how to do it in the PDF Documentation file.