The GitLab Container Registry originated as a fork of the Docker Distribution
Registry, now CNCF Distribution, both distributed under Apache License
Version 2.0.

The first GitLab change on top of the upstream implementation was efe421fd, and
since then we have diverged enough to the point where we decided to detach from
upstream and proceed on our own path.

Since then, we have implemented and released several major performance
improvements and bug fixes. For a list of changes, please see differences from
upstream. These changes culminated on a new architecture based on a relational
metadata database and the original goal, enabling online garbage collection.
