As with the internal lightweight `git_commit_list_node` that avoids having to look up commits, I wonder if a `git_blame_hunk` should keep the timestamp from the commit and also a pointer to the `git_signature` of the author and then keep an array and/or hash of the `git_signature` objects in the `git_blame` object itself (so that it can "own" them instead of the hunk being the owner). This way it would be easy to do basic blame output without looking up each commit. The OID would be there if needed for full lookup, but the overhead of keeping around the author and timestamp would be low and allow this to be much more efficient.