url property
URL is the page, absolute, exactly as the engine gave it. It is also the dedupe key — one source per URL, and at most hostCap per host — and what a markdown citation in the answer is checked against, so a link in the prose always matches a URL here.
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? url;