Source Control in Azure DevOps (Best practices) by @dotnetcurry dotnetcurry.com

Once the code is written, it needs to be kept safe (so code is not deleted or corrupted) and for that, we maintain a copy of it. Sometimes, we make fixes to code that does not works as expected. As a precaution, the original code is kept along with the changed code. If the changed code works, we do not need the original code, but in case it does not work, we can always use the original code to start fresh and remove bugs.