Find it a bit confusing that the indices are sections and the sections are blocks, and the nodes can be indices or sections, which means that they can be sections or blocks, and the commentary  and function "zettel", but they aren't called zettel in the function.
Clashes too much with the domain, as described in NKBIP-1 and in my Uploader. Can we maybe agree on one naming convention and write it into the spec?
Also problematic because only 30041 are zettel, so adding more kinds would make it even more confusing because you'd be referring to wiki pages as "zettel".