How do you actually use it on a project? I see where you can order a dedicated piece of hardware, but I'd love to download this and replace pyttsx3 on my homemade IoT linux server.

But all I see is documentation, discussion of what they used to build it, and.... where's the actual softare?!?

and the source code is available at: https://github.com/MycroftAI/mimic3

There is currently a Docker image, DEB package, and PyPI release.