anchor.diff:  ```
   After deleting the 2 files, you can run the GC and it should free some space.
   
  -I wrote link:url[https://gist.github.com/gbougeard/48e190f931653f99aaea668dd03759ef, this script] to delete outdated digests for one specific or all images of a DR. It also estimates the size of the potential freed space after Garbage Collecting. It's an estimation because Docker images share layers (and so blobs) and the GC will not remove the shared layers (otherwise your DR will be corrupted).
  +I wrote link:https://gist.github.com/gbougeard/48e190f931653f99aaea668dd03759ef[this script] to delete outdated digests for one specific or all images of a DR. It also estimates the size of the potential freed space after Garbage Collecting. It's an estimation because Docker images share layers (and so blobs) and the GC will not remove the shared layers (otherwise your DR will be corrupted).
   
  -The future versions of the lnk:url[https://github.com/docker/distribution/issues, Docker Registry] should enhance the GC abilities because there are a lot of issues/questions about it.+The future versions of the link:https://github.com/docker/distribution/issues[Docker Registry] should enhance the GC abilities because there are a lot of issues/questions about it.
positive.code: ```
  *Do not rm blobs by yourself! Let the GC handle this part!*
  
  Attention: *rming files on the storage and running the GC are critical operations : your DR must be in Read-Only mode. No image must be pushed while you're performing those ops.*
  
  There are 2 files to `rm` to cleanly remove a digest :
  ```
  
negative.code: As I said earlier, there will be one reference stored for each Docker image pushed. So, if you update 10 times your Pull Request, there will be 10 references for the tag `myPullRequest` in the DR. Only one will be fetchable by the tag `myPullRequest` :
  
  `docker pull myImage:myPullRequest`
  
  The others 9 will be only fetchable by their digest :
  ```
  docker pull myImage@sha256:digest1
  docker pull myImage@sha256:digest2
  ...
  docker pull myImage@sha256:digest9
  ```
  
  Let's call those 9 references _outdated digests_.
  
  == How to clean references?
  
  link:https://docs.docker.com/registry/spec/api/#deleting-an-image[Using the DR HTTP API] : 
  to delete a tag, you need to delete its manifest, and to delete a manifest you need its digest.
  
  Accessing the DR storage filesystem.
  If you have access to it, you can rm some files but you must be sure of what you are doing because you can easily corrupt your DR. The storage file tree is described link:https://github.com/docker/distribution/blob/master/registry/storage/paths.go#L21[here].
  
  ```
  // The path layout in the storage backend is roughly as follows:
  //
  //		<root>/v2
  