Wasn't sure about using it for a leaderboard, so I just gave it a few quick tests.
I uploaded two files and then examined the links (location) for the download button.
I used that path in an AppGameKit app with the
OpenBrowser() command, and it gave me the download with the typical Open/Save file box you have with any download.
Curious about the path simply having a sequential number to represent the file that was not random, nor unique for my account, I attempted to download a file that I had uploaded then deleted and got a 404 file not found error.
So, then I picked a random number much less than my files had and got a 403 Access denied error.
So, it appears that TGC has a simple method for identifying these files, and an internal method to block users from accessing someone else's file.
Both of those tests were done when I was logged in and both files were uploaded as a regular file.
When logging out and then trying the link again, it took me to the login screen, and then when i logged in, it took me to the dialog to open ir save the file.
So, then I uploaded another file as a 'AGK Cloud Save" and got the next sequential number.
I had the same results when trying to access the file for download via a browser, which was dependent on my being logged in.
So, while I think TGC is offering us a place to have backup storage for our games, I do not see a way to access these files from an app, unless you are already logged into their website and it is you who is making the request.
Hope this helps to answer your question.
Coding things my way since 1981 -- Currently using AppGameKit V2 Tier 1