What is CVS?
During software developement it is a good idea to keep track of what changes were made, by whom and when. It is also sometimes nessassary to roll back changes and and /or keep several branches of the source code. CVS is a version control system that does this for you. As a user you don’t really need to know about it unless you want to download the very latest changes and compile blender yourself.
GreyBeard