Metadata in PDFs is also typically based on semantic web standards. https://www.meridiandiscovery.com/articles/pdf-forensic-analysis-xmp-metadata/ https://www.

Metadata in PDFs is also typically based on semantic web standards. https://www.meridiandiscovery.com/articles/pdf-forensic-analysis-xmp-metadata/ https://www.meridiandiscovery.com/articles/pdf-forensic-anal... Instead of using JSON-LD it uses RDF written as XML. Still uses the same concept of common vocabularies, but instead of schema.org it uses a collection of various vocabularies including Dublin Core.