The Microsoft Edge team has proposed a native Split Screen API that allows opening a URL side-by-side using the _split target:

// Target behavior: opens the URL in a split-screen pane
window.open("https://example.com", "_split");

In browsers where this isn't supported, _split is treated as a standard named window, opening a new tab instead of a split pane. I need to implement a fallback (e.g., an internal iframe layout) only when the native feature is unavailable.

I've searched navigator.userAgent and window properties but haven't found a reliable flag for this specific API support.

Is there a way to programmatically detect if the browser supports the _split window target?