If not set explicitly with --file, there are four files where git config will search for configuration options:
...
$(prefix)/etc/gitconfig
System-wide configuration file.
What is $(prefix) on $(prefix)/etc/gitconfig?
If not set explicitly with --file, there are four files where git config will search for configuration options:
...
$(prefix)/etc/gitconfig
System-wide configuration file.
What is $(prefix) on $(prefix)/etc/gitconfig?
The prefix environment variable git was compiled with. Usually, it's /usr/local, so the path is /usr/local/etc/gitconfig.
More information can be found in the INSTALL file in the git repository.