Rumor: Other Song From Finale Leaked?

(source)

So a song has been released that people are claiming is the other song from the finale. The earliest occurrence I can find is from here: one of the Friendship Is Witchcraft folks posted it. I suppose they'd have a motive but this begs the question: how did they come across it in the first place?... Anyways, potential spoilers past those links, of course. Thanks to Marshall for letting us know!

Edit: The general consensus is they be trollin': probably not a FiM song.