Yeah I had to double check as well. It actually does elaborate.
“AMDGPU PRO OpenCL - used because Mesa OpenCL is not fully complete. Proprietary component only for Polaris GPUs. The onward GPUs use the open ROCm OpenCL.”
So for anything newer than the RX 500 series (anything after 2017) it doesn’t matter for OpenCL it seems.
From what I can gather the OpenCL stack used to be proprietary, but they decided to open source it when ROCm came along. So the Pro driver used to be more important and now it’s really only necessary for AMF since the Vulkan and OpenGL portions are straight up worse than mesa.