By that logic, if I fork chromium and make a custom version of it that's hard-coded to start up HN in the first tab, then I've made a native HN app.

No, you've "made" a native browser that opens HN in the first tab.

By that logic Postman native is a native browser hardcoded to open only one tab and load Postman's javascript code upon start-up

Basically this is true but the browser (Electron) is designed to be single-purpose (your app) and has pathways to the filesystem that you can't get in a web browser.

Also, it is treated as an application by the OS rather than a Chrome window (and all the benefits that come with that shift).

But you won't have access to the file system unless you further modify it.

That just makes the platform native, which doesn't say anything at all. Presumably the app itself is still written in javascript, so its not native at all - its just bundling its own (native) copy of chrome.

So are you saying anything with a runtime is not native, even if embedded in an executable? Is a go app native?

Does a go app use the native toolkit?

QT isn't native either.

Actually, Qt (as in Qt Widgets) is a peculiar case. Qt draws its own widgets, but on some platforms uses native theming APIs to draw widgets (e.g. HITheme in macOS[1]). Though they are apparently experimenting with native widgets now [2].

So I'd say Qt is more native than e.g. Electron, but it is definitely not completely native. Except on Linux of course.

[1] http://doc.qt.io/qt-4.8/qmacstyle.html#details

[2] http://blog.qt.io/blog/2017/02/06/native-look-feel/

The technical sense meaning it's not interpreting some random scripting language and rendering with HTML/dom?

Because that's the meaningful sense.