Nvidia.runtime passing what?

I’m finally looking at doing some nvidia passthrough and came across the nvidia.runtime option, I am wondering how much it passes. Is it just the drivers, or would say nvidia encode/decode libraries also believe passed to the container? Is there documentation of exactly what is passed?

The container runtime is made by Nvidia, GitHub - NVIDIA/nvidia-container-toolkit: Build and run containers leveraging NVIDIA GPUs

Here is the documentation, Architecture Overview — NVIDIA Container Toolkit