The readme says that it’s a demo. Sounds more like source available than open source in that case. Or has it changed to open source and the readme is out of date?
Also, is the available source complete or does it download any additional components from your company when you run it that are only available in binary form?
There is a MIT license in the repo. In that sense it's open source.
It's using "Edge TTS", which I believe means using API keys [1] stolen from Microsoft Edge and hoping Microsoft doesn't sue you, non jolly-roger flying internet users beware.
Can't speak to other models and their licenses, I stopped looking after I saw edge-tts since I don't feel the need to use this.
Also, is the available source complete or does it download any additional components from your company when you run it that are only available in binary form?