Component image 
Material Relay component as seen in the Scene Inspector

The MaterialRelay component is used to specify to a Material Tool when hitting a slot what materials to grab/apply to when using the tool.
Fields
Name | Type | Description |
---|---|---|
persistent
|
Bool | Determines whether or not this item will be saved to the server. |
UpdateOrder
|
Int | Controls the order in which this component is updated. |
Enabled
|
Bool | Controls whether or not this component is enabled. Some components stop their functionality when this field is disabled, but some don't. |
MaterialRefs
|
list of AssetRef`1<Material> | A list of material storage fields that a material tool when applying should apply to. The first non null item in the list is the one a material tool will pick up when using the secondary action. |
Usage
Attach to the root of an object and provide a list of material storage fields from, for example, Component:MeshRenderer or Component:SkinnedMeshRenderer to make Relays for.
Examples
Added to the root of new avatars made with the avatar creator.