ModelCredit typedef
What an export owes somebody for one object — gal-05.
Four fields, because a credit that cannot be checked is not a credit. A name alone leaves whoever reads the exported file unable to find the original or the terms; the licence and its URL are what make the line answerable.
Implementation
typedef ModelCredit = ({
/// What the thing is called where it came from.
String title,
/// Who to credit. Never empty — `gal-01` refuses an item that asks for
/// a credit and names nobody.
String author,
/// The licence's own name, as the card showed it.
String licence,
/// Where the licence text is.
String url,
});