"would be using Sciter for embedded apps" that is not a problem already. E.g. it runs on ARMs like Raspberry Pi. SDK contains binaries that use GTK but it is possible to run it without any window manager. Access to FB or video memory is enough.

As of OpenSource, yes I have plans for that. The only problem is that OS is a great responsibility, at least for me. It is going to be a significant effort to document source code, etc. I am actively looking for sponsors for the effort.