How does one achieve a file pointing to another server using random alphanumerical characters?

I visited a website, and it has download buttons, but each download button has a randomly generated value, ex:https://www.example.com/downloader/VSyxys31A3JBJyVe7kk4NA/1582649176/d128_cdn/18363, which when clicked downloads the file from another website, http://cdn1.example2.com/download/VSyxys31A3JBJyVe7kk4NA/1582649176/t/2020/folder1/128/filename.mp3

How is this possible?. How does one achieve this?