You have CAD models for FreeCAD or other?
I registered online on onshape.com , but see by your link from GitHub only screw.
So I should change the link so it opens to a different model it seems, but all the models are there in the tabs at the bottom of your view, underlined in red below. Though what is better is to click the little icon circled in green on the bottom left, which expands a tree view showing all the models.
The whole set of models is poorly organized. We have been doing a very exploratory development cycle for three years. Once we have a final production kit design, we will archive this development fork and make a clean version of the files with well organized models.
That said, you can explore what we have now and get a feel for where things are going!
Hope this helps. Glad to see you opening things up!