If you want to replace many blobs, trees or commits that are part of a string of commits, you may just want to create a replacement string of commits and then only replace the commit at the tip of the target string of commits with the commit at the tip of the replacement string of commits.

As of Git 1.6.5, the more flexible git replace has been added, which allows you to replace any object with any other object, and tracks the associations via refs which can be pushed and pulled between repos.

[Old commit references] Provide a way for users to use old commit IDs with the new repository (in particular via mapping from old to new hashes with refs/replace/ references).