Today, I got across the git feature conditional_includes. You can specify which git configurations should be applied under which circumstances.
As a software engineer I am used to work on different projects and sometimes for different organizations. I do not want to use the same e-mail address for all git repositories. I made use of the git local configuration to specify the e-mail address I want to show in my git commits for the corresponding git repository (for example: git config --local user.