

ROCm is an implementation/superset of OpenCL.
ROCm ships its installable client driver (ICD) loader and an OpenCL implementation bundled together. As of January 2022, ROCm 4.5.2 ships OpenCL 2.2
Shaders are computational visual [post-]processing - think pixel position based adjustments to rendering.
OpenCL and CUDA are computation frameworks where you can use the GPU for other processing than rendering. You can use it for more general computing.
nVidia has always been focusing on proprietary technology. Introduce a technology, and try to make it a closed market, where people are forced to buy and use nVidia for it. AMD has always been supporting and developing open standards as a counterplay to that.
Man this was hard to find for some simple release notes when you’re already looking at the announcement of it…