The Reanimate site says that it ships with Chipmunk2D, and the example I linked shows both

  import Chiphunk.Low
  import Reanimate.Chiphunk

However I can't find any reference to Reanimate.Chiphunk anywhere, and if I search the repo for "chiphunk" I just see this example file, the readme, and a couple of YAML files. So I am very confused now.