Here is the link to the documentation, it explains it better than I can without copying it verbatim: * https://git-scm.com/docs/git-update-index#_untracked_cac

Here is the link to the documentation, it explains it better than I can without copying it verbatim: * https://git-scm.com/docs/git-update-index#_untracked_cache https://git-scm.com/docs/git-update-index#_untracked_cache The underlying filesystem needs to have certain features enabled (mtime of directories) to be able to support the untracked cache. There's no guarantee that all will, so it does not enable it. I suppose this could be enhanced to be an opportunistic feature. However, then there is some variability in what git is doing versus there being one default behavior.