The primary purpose of publishing these files is to enable the lowest levels of the board-building ecosystem (where I reside) to experiment with building these boards at the lowest cost. Lots of people have local access to laser cutters, and cardboard is ubiquitous, so widely distributed low-cost production of these core kits is possible.
Bottom line: if you really want to build one of these boards, and can’t get a core kit from me for whatever reason, here’s a way to make your own.
If you build a board from these files, I will be thrilled to see pictures of the results. I’ll feature the first response on my project web site.
[Thanks, Charles Pax!]