Talk:What About Discord?/@comment-25270260-20160207030227/@comment-32136229-20160207071200

That's not what "extra" means. According to Wikipedia, "extra" means:

"[A] performer in a film, television show, stage, musical, opera or ballet production, who appears in a nonspeaking or nonsinging (silent) capacity, usually in the background (for example, in an audience or busy street scene)."

Zecora's role in this episode does not match that definition. It's more of a cameo than an "extra" appearance.