things to review:
- name not following naming convention
- extending from nt:unstructured
- OPV flags (behavior upon versioning of the parent node)
- incomplete list of properties compared to those mentioned in query.md
- 'async' property is string with a predefined value 'async': why not boolean?
- index content stored underneath the definition has not dedicated node type.
things to consider:
- is it expected that an index definition has custom properties?
- is it expected that such custom properties have other property types that STRING/NAME/BOOLEAN? e.g. a binary?
- is it expected that an index definition has other child nodes that the index content itself?