Private cloud compute I think. I learnt about it today too from this reddit post which mentions how:

> At WWDC, Apple announced that starting in the 27.x versions of iOS, macOS, etc., devs would be able to call Private Cloud Compute directly from Swift with no additional API configuration. Presently, the only way to get free cloud inference is by joining the App Store Small Business Program.

https://www.reddit.com/r/appledevelopers/comments/1vztibh/re...