For context: https://creativecommons.org/2017/06/22/unsplash/
"Following the switch to the new Unsplash-branded license, there is no marking of works that were previously shared in the public domain using CC0. The Unsplash API restricts/obscures the full CC0 collection, which we believe to be about 200,000 images, but it isn’t possible to access the complete archive. In order to ensure that the commons is maintained, we hope that Unsplash will either a) properly mark all the works shared using CC0 and/or b) make available a full archive of the CC0 works so they can be shared on a platform that supports open licensing and public domain tools. Previous platforms that have gone under or abandoned open license tools have shared their CC archives for this purpose. We hope Unsplash will follow the same path."