In the time of AI LLMs, "classic" content management tools and techniques look obsolete.
But they are not, just not mainstream, because they are complex/not easy.
In fact, maybe by leveraging AI tools such tools and languages may actually be more useful.
Same as complex programming languages, like Rust, that can now be usable with more people.
SHACL - Wikipedia
Shapes Constraint Language[1] (SHACL) is a World Wide Web Consortium (W3C) standard language for describing Resource Description Framework (RDF) graphs. SHACL has been designed to enhance the semantic and technical interoperability layers of ontologies expressed as RDF graphs.[3]
SHACL models are defined in terms of constraints on the content, structure and meaning of a graph. SHACL is a highly expressive language. Among others, it includes features to express conditions that constrain the number of values that a property may have, the type of such values, numeric ranges, string matching patterns, and logical combinations of such constraints. SHACL also includes an extension mechanism to express more complex conditions in languages such as SPARQL and JavaScript. SHACL Rules add inferencing capabilities to SHACL, allowing users to define what new statements can be inferred from existing (asserted) statements.
Status Published, W3C Recommendation[1]
W3C Recommendation 20 July 2017