Docker Hub can store images for the build workflow.
Docker Hub integration for the Drupal 11 stack
Docker Hub fits into this stack through Docker Hub workflows. This page explains how it is actually used with the Drupal 11 stack, not just that the provider exists.
How Docker Hub 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 11 stack.
Store built images for releases
Docker Hub can hold images produced by the stack build workflow so releases keep the same deployment path.