In general, the analogue to reference types in ProtoFlux is the object type. However, they are not equivalent, as ProtoFlux is separate from FrooxEngine and thus does not inherently know its data model. This can cause some confusion when using nodes that interact with FrooxEngine (such as a Data Model Store) vs nodes that are contained entirely within protoflux (such as a Local). A slot is an Object Ref in the data model, but an Object alone in ProtoFlux contexts. A string is a value in the data model, but an Object Field in ProtoFlux contexts.