That's exactly how you store a tree in a relational database. Every row has a parent_id column. This language isn't just a tree though, it's a graph, so you would need a row per edge instead of a row per node. It would work with git as long as it's kept in sorted order and doesn't grow extremely large, but it isn't nice to view or edit directly; you would want a graph query language to interact with it.

That would work as long as the author isn't seriously abusing reader macros in the serialized format :).