About architecture of Oculus Integration SDK

What is the relationship between Unity XR Interaction Toolkit and Oculus Integration SDK?

I can see in C# script, Oculus Integration SDK referred Unity XR SDK objects, like:

using InputTracking = UnityEngine.XR.InputTracking;
using Node = UnityEngine.XR.XRNode;
using NodeState = UnityEngine.XR.XRNodeState;
using Device = UnityEngine.XR.XRDevice;

Does Oculus Integration(Interaction part) SDK implementation make use of Unity XR Interaction Toolkit?

Thanks in advance.