I don't think non-standard is accurate, as generalized triples/graphs/datasets are in rdf11-concepts, which is a standard. That spec just notes interoperability issues, rather than considering generalized rdf to be non-standard:


> It is sometimes convenient to loosen the requirements on RDF triples. For example, the completeness of the RDFS entailment rules is easier to show with a generalization of RDF triples. Note that any users of these generalized notions need to be aware that their use may cause interoperability problems, and that there is no requirement on the part of any RDF tool to accept, process, or produce anything beyond regular RDF triples, graphs, and datasets.

> A ___generalized RDF triple___ is an RDF triple generalized so that subjects, predicates, and objects are all allowed to be IRIs, blank nodes, or literals. A ___generalized RDF graph___ is an RDF graph of generalized RDF triples, i.e., a set of generalized RDF triples. A ___generalized RDF dataset___ is an RDF dataset of generalized RDF graphs where graph labels can be IRIs, blank nodes, or literals.