Null-aware elements offer a shorthand for adding an element to a list, if the element is non-null. Consider this code before the feature:

Stack(
  fit: StackFit.expand,
  children: [
    const AbsorbPointer(),
    if (widget.child != null) widget.child!,
  ],
)

This causes repetition of widget.child, and is verbose. With null-aware elements this becomes:

Stack(
  fit: StackFit.expand,
  children: [
    const AbsorbPointer(),
    ?widget.child,
  ],
)

Now that the framework has adopted Dart 3.8 (#171703), we can adopt this feature in the framework too!

cc @justinmc and @loic-sharma for visibility. :)