This page contains information about Oculus integration in OctoXR and Oculus platform specific scripts defined in it
For integration with Oculus platform OctoXR uses the Oculus Integration package that can be found on Unity's asset store.
At the moment, in use is very minimal part of the whole Oculus Integration package, there are a few scripts from the package that the OctoXR relies on, namely the ones attached to OVRCameraRig prefab found in the package. In fact that prefab is the only thing from the package that's needed usually.
In addition to that input is read using Oculus' package low-level public API, so no scripts or prefabs or any other assets are used for that.