In the example we have

license:
name: CC-BY 4.0 license
url: https://creativecommons.org/licenses/by/4.0/

I see looking at https://spec.openapis.org/oas/latest.html#license-object-example that a fuller response might be:

license:
name: Creative Commons Attribution 4.0 International
identifier: CC-BY-4.0
url: https://creativecommons.org/licenses/by/4.0/

But I can't work out from the example how a user of the service would know who to attribute (i.e. give appropriate credit) as is required by the licence

Attribution — You must give appropriate credit , provide a link to the license, and indicate if changes were made . You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.