The idea is that it slices the Amen Break into however many slices you specify, and the list being sorted is the indices for those slices. At each step, it plays the slice the pivot is being compared to.
Because it only plays the samples being compared, it never plays the sorted chunks, so it's missing a "punchline" of sorts.
> e.g. the mantra of 'upstream early; upstream often'
This is the gold standard, sure. In practice, you end up maintaining a branch simply because upstream isn't merging your changes on your timescale, or because you don't quite match their design — this is completely reasonable on both sides, because they have different priorities.