sparqdown-graph labels namespace
The sdgl: namespace holds the registry's built-in labels — the Label IRIs applied via sdg:hasLabel to classify a document's nature, such as sdgl:core-vocabulary, sdgl:documentation, and sdgl:technical-requirement. The loader reserves this namespace for the registry; organisations declare their own labels under their own namespaces.
Membership in this namespace is derived by the Lexicon from the declaration above — see Namespace Definition.