[IfOnlyYouKnew]

They do only have an API and the (trained) model (parameters) are not released. But I believe the "semi-public" here refers to the fact that access to the API is limited to invitees (with the ability to add your name to a waitlist).

[lopsidedBrain]

Huh, for some reason I had just assumed that it must be open based on the buzz around it. Cool.