Objects which can be equipped and rigged using the Prefab and Object Manager should have an Equipment Object component on them. This provides advanced functionality for the Prefab and Object Manager, making it easier to create Prefab Groups for wardrobe, and specifically tells the script which bone is the root bone, and the skined mesh renderer for the object.
Wardrobe from Infinity PBR will already have this component attached, so you do not need to do anything to set it up!
Objects that do not have a Skinned Mesh Renderer and aren't intended to be rigged to the parent object they are attached to, do not need this component. The Prefab and Object Manager can handle any object or prefab.