The other answer to the question zeroheight answers. Where zeroheight documents a system that lives elsewhere, Knapsack wants to be the system's home: the token source, the pattern composer, the rendered components, and the prose, with Figma and the repo as integrations rather than the truth. Worth measuring against the estate's own split — Figma file, AEM reference site, zeroheight — which is three tools doing what this claims to do in one.