Is there a supported way for developers to purge locally downloaded Photos originals/resources in order to force an asset/resource into a non-downloaded iCloud-only state? Basically simulate "Optimize Mac Storage" behavior on demand for testing.
Thanks!
There is no supported way to purge resources on demand. In general these resources are managed by the system as disk space becomes limited and needs to be freed.
If you have a particular workflow or testing that you are trying to achieve I'd recommend you file a feedback detailing what you're trying to achieve.