My guess would be that the first prototype that they made was too buggy to publish. The promise is that they will share the final design, and I am fine with that.
(I am not affiliated with the project, but backed it)
Yikes. If I'm understanding that correctly every chip that came back from MPW-1 was more or less unusable - they were all required to gate access to I/Os behind the same management processor provided by the company organising the run, and because that management processor was broken they couldn't configure the I/Os to route through to their own designs.
(I am not affiliated with the project, but backed it)