That or they could just open their GPU cores to direct programming instead of locking it behind some API.
It also claims to do this across radically different architectures like FPGA and all I can say to that is "I find that very hard to believe"
One common instance is, blender's Cycles renderer. Every time there is a new NVIDIA GPU. It needs to be recompiled to support it. Sometimes that also requires a new CUDA version to be able to do it. CUDA versions over the years have deprecated different operations and what not.
Although for completeness I'll note that Intel's GPU architecture is documented: https://01.org/linuxgraphics/documentation/hardware-specific...