What is the difference between the projects folder and the websites folder in the file system?

 I just copied and pasted a copy of my current project into the projects folder in the file system.  I created this copy as a backup that I can revert back to if I screw up the other one. 
Why is this copy in the projects folder but not in the websites folder?  It is also a website.  I know that is where I pasted it.  But I never put the other one into the websites folder.
 
thanks for any help. 
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