The additional layers that this Collider should include when deciding if the Collider can contact another Collider.
The Layer Collision Matrix defines which layers can contact other layers. Use this property to specify additional layers that this specific Collider instance can contact.
NOTE: Layers can be included or excluded differently depending on the settings of each Collider instance. As such, there could be a conflicting decision for whether two Collider instances can come into contact with each other. To learn how Unity decides this, see Collider.layerOverridePriority.
Additional resources: Collider.excludeLayers, Rigidbody.includeLayers, Rigidbody.excludeLayers, ArticulationBody.includeLayers, ArticulationBody.excludeLayers.