So if I understand right, what makes this lighter than electron is the fact that only webkit2 is used instead of embedding the whole chromium app.
I see mentions of WKWebView(the system webkit) in the code[0], and while I don't know any Windows programming, they are #including [1] - looks like a system included web view (presumably the one that edge was based on). The linux build requires libwebkit2gtk-4.0-dev to be installed[2] - they're dynamically linked to webkit2gtk.
[0] https://github.com/neutralinojs/neutralinojs/blob/b10e065c97...
[1] https://github.com/neutralinojs/neutralinojs/blob/07fdc3c1c7...
[2] https://github.com/neutralinojs/neutralinojs/blob/master/REA...