The number is callcalled a GUID (Globally unique identifier) and it is used a lot under the hood in Windows and many other IT systems.
This particular value is a constant for the 'Microsoft CopyTo Service'"Microsoft CopyTo Service." At some point, sometime someone and Microsoft (and someone else) made this up and since then that string of characters is used to identify that particular feature of Windows.
There are many different types of objects in Windows that are identified with GUID. Normally, the user is shielded from seeing these, but when you edit the registry, you usually come across them.
This one may be therehave been present since Windows 95Windows 95.