DEMO Question - (Rigging)

Not sure if that is the right question. When you purchase hair or a item that has that floating DEMO attachment. How do they get that attachment? Do I have to rig and make something in blender, when I am rigging my mesh clothes to the Dev kit? I hope this question makes sense.

5f44b5340a1377f498b94dfacff89e7d.png (gyazo.com)