They’re moving a lot of code to this internal core, which means this core is unstable. It’s pretty common for projects to hold off on making code public until it’s reached a certain level of stability. I’m guessing they’re not interested in accepting patches, due to the high level of churn from the dev team. Once that churn dies down, there’s a chance they’ll reconsider and make it FOSS.

I’ve seen this in a number of FOSS projects, and it’s also what I do on my own (I don’t want help until I’m happy with the base functionality).

So that’s why I hold out hope. We’ll see once the churn on that internal SDK repo dies down.