Finally, Anytype export/import has a file format that exports every aspect of our objects, including relations and links. But sadly, the file format isn’t readable outside of the Anytype application. 
From the little I understand of the protobuf format so far, if the Anyteam gives us the .proto files to go with the .pb files that get exported, the community could then write scripts that edit them in bulk. This would be almost as good as giving us a public API because it would open up the way for code-generated objects.