The closed-source user-space component isn't new, the drivers always contained a kernel module and user-space libraries. Those libraries provide an OpenGL and Vulkan implementation. It's equivalent to Mesa for AMD and Intel GPUs (and the kernel driver is equivalent to amdgpu and i915 respectively).

Since it's closed we can't really know for sure if anything was moved to it from the kernel, but I think it's quite unlikely something like HDMI link setup was moved to user-space instead of to firmware.