So, http://schema.org/ stores schemas describing a significant subset of all things ever. It's intended to use to mark up HTML so crawlers can more intelligently understand what's on your page. Is `avatar` a movie, a show, or a profile image?
I'm experimenting with using schema.org's schemas in databases, saving myself time modeling my data, and making the aforementioned HTML markup easier. Part of that experimentation is this API, and using it to auto-generate schemas.