[Windows phone 8.1] Getting a handle on memory usage

[PBC_FL]

It's pretty obvious that Spotify is storing its downloaded material in the main phone memory and not in the SD card. I understand this is because M$ doesn't allow apps to access that (at least at the time the Spotify app was developed).

Am I able to access or at least see the files that this app produces so that I can get a handle on what kind of memory usage I'm using for this vs. other apps? I have the "files" app that lets me browse file, but I can't see any files associated with this app either through the computer interface or through the files app.

I'm assuming it is because only the app can see and expose memory allocated to it. Any thoughts, comments, etc from the more windows phone OS literate among us?