Today I will introduce you to the program etckeeper, a simple tool that track changes in your /etc/ directory into a versioning control system (git, mercurial, darcs, bazaar...).
Your system may certainly package it, you will then have to run "etckeeper init" in /etc/ the first time. A cron or systemd timer should be set by your package manager to automatically run etckeeper every day.
In some cases, etckeeper can integrate with package manager to automatically run after a package installation.
While it can easily be replicated using "git init" in /etc/ and then using "git commit" when you make changes, etckeeper does it automatically as a safety net because it's easy to forget to commit when we make changes. It also has integration with other system tools and can use hooks like sending an email when a change is found.
It's really a convenience tool but given it's very light and can be useful I think it's a must for most sysadmins.