Seek bar icon feature?

[mario1230 4]

I made a similar post on reddit a while ago but figured I'll try here as well. 

I was watching Space Jam the other day and noticed the seekbar had a basketball icon instead of the regular icon. I've never seen this changed on anything else. Thought it was maybe a new feature and a great idea. Is this icon somewhere in my folder? If so, I can't find it. or is it built into the container of the file? Apparently it will also show a pumpkin icon for Halloween movies.