Comment by nrp

We will be releasing specifications and reference designs for the Expansion Card system under a permissive license. We want to make it easy for both other companies and members of the community to develop their own cards and sell them through the Framework Marketplace. That is something we'll be detailing and sharing between now and the time we start shipping out the product. We'll also provide documentation around internal interfaces, though those will be more technically challenging for an individual to be able to build something with.