[t0mek]

> although organizing it like a virtual FileSystem does have a certain appeal, and unfortunately I don't know of a database engine that supports such a layout

Apache Jackrabbit Oak [1] implements a tree-format data model called JCR [2]. It's used as database engine for the Adobe Experience Manager (enterprise-level CMS).

[1] https://jackrabbit.apache.org/oak/docs/ [2] https://en.wikipedia.org/wiki/Content_repository_API_for_Jav...