lang property
Lang is the language the indexer parsed the file as ("go", "python", …), or empty when it recognised none — in which case Symbols is 0 because nothing was extracted, not because the file declares nothing.
Please note: This property should have been non-nullable! Since the specification file does not include a default value (using the "default:" property), however, the generated source code must fall back to having a nullable type. Consider adding a "default:" property in the specification file to hide this note.
Implementation
String? lang;