> core set of platform agnostic native widgets This is confusing for me. I think such a framework is either 'platform agnostic' OR 'native'. Maybe the API is platform agnostic and the rendering is done natively?
That’s the case, yes – the UI runtime is Qt5 (which is rendered using low-level graphics APIs, so we class it as “native” – mostly in contrast to WebView-based UIs), and it’s the same API regardless of which platform you’re running on.
An example of native UI is libui or WxWidgets.