Merkle trees and build systems

Well, Docker has *finally* implemented OCI image support (which just boiled down to supporting the metadata blobs, since the layer blobs were designed to be identical between the Docker v2.2 image format and the OCIv1 image specification). So it's entirely possible they'll support the extensions we're working on, but I wouldn't hold out hope that it would be a quick transition. containerd and podman/cri-o will probably pick them up faster (though I think podman/cri-o will require more extensive changes to their storage internals since they're based on Docker's graphdriver code).