If you are looking to to print shapes of a poppy-ergo-jr, you can download STL files on the last GitHub release.
The up to date hardware version is made with Onshape, which is a proprietary online CAD software, free to use for public projects.
You can view and modify the hardware parts on Onshape (link of the onshape project), but an account (free) is required.
The OpenScad version of hardware is kept here for memory and educational example of an OpenScad project, but it is no longer maintained.
An alternative version made by S. Brunel can be found on Thingiverse.