Are there any papers or such that have any details about what allows k/q to be so fast? Or would those be considered implementation secrets? It's always nice t

Are there any papers or such that have any details about what allows k/q to be so fast? Or would those be considered implementation secrets? It's always nice to be able to read about the technology and design underpinning something, but in this case at least it'd be understandable if that were not available.