It's unclear whether being able to insert a new identifier within an existing list of identifiers is a feature. That might just be a byproduct of needing to put the new card into a related area. The Zettelkasten.de software appears to be pushing concepts that would have been impossible in Luhmann's system. Ultimately it seems that all these information systems are just different implementations of nodes, edges, and c…
I was thinking a textual based system would be easier to version control and source, maybe something similar to mermaid [0].