No idea. I just stumbled upon it on Youtube.
And actually looks like it was discovered 2 years ago, as I found another Youtube channel that has had it longer:
https://www.youtube.com/watch?v=mH7tFcAvfZI
Read the comments on it for some more info.
Also, if you click on PlayLists:
https://www.youtube.com/channel/UCVS...medA/playlists
There are games from the Seattle Pilots, and numerous announcers etc. Good stuff to fall asleep too too!