Distribution Registry can store images for the build workflow.
Distribution Registry integration for the Drupal 10 stack
Distribution Registry fits into this stack through Distribution Registry workflows. This page explains how it is actually used with the Drupal 10 stack, not just that the provider exists.
How Distribution Registry is used with this stack
The provider is useful only when it fits a concrete workflow in the stack. These are the roles it can play around the Drupal 10 stack.
Store built images for releases
Distribution Registry can hold images produced by the stack build workflow so releases keep the same deployment path.