https://packagist.org/packages/wikibase/data-model
https://packagist.org/packages/wikibase/data-model-serialization
https://packagist.org/packages/wikibase/data-model-services
https://packagist.org/packages/wikibase/internal-serialization
https://packagist.org/packages/wikibase/term-store
(Actual codes are hosted in GitHub)