Background Pony #EBCA
It’s just a design an artist came up with 9+ years ago and made a Tumblr for. If there’s more significance to the specific attributes, you might have to ask them but IDK if they’re around at all any more.
(NSFW link obviously)
https://web.archive.org/web/20131101024912/http://apony-shy.tumblr.com/
https://web.archive.org/web/20131101024912/http://apony-shy.tumblr.com/
“You may or may not have already seen this, it’s the first drawing of fluttershy with this hoodie that I made on the mlp flockmod room some time ago, I finally polished it so I could add it to my collection.”