Function focused_environment 

pub fn focused_environment<T>() -> Option<T>
where
    T: Clone + 'static,

The ambient T of the window that currently has focus (docs/state.md): SwiftUI’s @FocusedValue.

environment answers “what did my ancestors provide”, which is the right question inside a piece and the wrong one inside an app-wide menu action: a desktop menu bar is one bar for the whole app, and its commands act on the front window. This resolves through that window’s own scope instead of the calling scope, so File ▸ New Item adds to the list the user is looking at. A cover that provides no T answers with the primary window’s, since the cover renders inside it (following the window scope chain). None ⇒ no window is open, or the front one provides no T.