This directory used to contain scripted implementations of builtins that have since been rewritten in C. They have now been removed, but can be retrieved from an older commit that removed them from this directory. They're interesting for their reference value to any aspiring plumbing users who want to learn how pieces can be fit together, but in many cases have drifted enough from the actual implementations Git uses to be instructive. Other things that can be useful: * Some commands such as git-gc wrap other commands, and what they're doing behind the scenes can be seen by running them under GIT_TRACE=1 * Doing `git log` on paths matching '*--helper.c' will show incremental effort in the direction of moving existing shell scripts to C.