This is the URL that Google references when issuing a DMCA takedown.
This should be a link to your product; you can use a Soundcloud link, a product page (Spotify, iTunes, Beatport, etc.).
Copyright URLA copyright URL is a reference link for your product.
This should be a link to your website, or anything that corresponds to your album and/or record label.
Google has removed that URL from their indexes so people can't find that link when searching Google.
The URL or content within has been removed from the website.
Why the differentiation?
Not all websites are in compliance with DMCA takedown laws. Usually they reside in countries where there is no enforcement of the protection of IP/copyright.
So by having Google de-index these links the vast majority of people can't stumble into the content. They would be able to do so if they have the direct link to the website in question.