This is enabled in home-manager becuase Git attempts to hardcode the path when it is done through Git. Enabling Git in home-manager creates a managed config at $XDG_CONFIG_HOME/git/config, but if ~/.gitconfig exists, git will use that instead which still allows for mutable config. The activation script is configured to automatically create ~/.gitconfig if it doesn't exist, so everything should still work exactly as before.
home
This directory contains modules and configuration specific to my home-manager
configuration. default.nix
is the entrypoint to my module set; it can safely
be loaded without making any configuration changes by default.