> If the author is here, please understand that there is no "native" UI toolkit for Linux or BSD.
You're wrong. When a library is native to some system, it does not mean that it is always shipped with the system. It means that it runs directly, without an interpretation layer in the runtime.
So GTK3 is native to Linux/Xorg. The desktop environment is irrelevant, and may not be based on GTK3.
The phrase "Each platform’s native UI toolkit" suggests that each platform has one specific native toolkit. That misconception is what I was addressing.
To put it in practical context, apps built with Gtk generally stand out like sore thumbs on Qt-based desktops like KDE Plasma, both in the way they look and in the way their widgets respond to input. This rather undermines the app's claim "to deliver the best experience" with its choice of UI toolkit.
But if you like, go ahead and believe that I'm wrong instead of trying to understand.
There are 'hacks' around this, which style one toolkit/widget set from another, in combination with themes/styles for these. Not for any combination by far, but some do exist. I think that started with RedHats Bluecurve. And then got harder with with later GTK3 and their forced (lib)Adwaita-crap and CSD.
You're wrong. When a library is native to some system, it does not mean that it is always shipped with the system. It means that it runs directly, without an interpretation layer in the runtime.
So GTK3 is native to Linux/Xorg. The desktop environment is irrelevant, and may not be based on GTK3.