One noteworthy difference is that in the original repository format, a tree object was just a list of named blobs. Nowadays each subdirectory of a tree is its o

One noteworthy difference is that in the original repository format, a tree object was just a list of named blobs. Nowadays each subdirectory of a tree is its own nested tree object, which means that when you're comparing two trees, you can skip over the directories that are identical. I'm not sure when that change was made but it must have been very early on, because the repository format has been basically stable for many years now.