Gtk.Widget.prototype.drag_get_data

function drag_get_data(context:Gdk.DragContext, target:Gdk.Atom, time_:guint32):void {
    // Gjs wrapper for gtk_drag_get_data()
}

Gets the data associated with a drag. When the data is received or the retrieval fails, GTK+ will emit a Gtk.drag-data-received signal. Failure of the retrieval is indicated by the length field of the @selection_data signal parameter being negative. However, when Gtk.Widget.prototype.drag_get_data is called implicitely because the Gtk.DestDefaults.drop was set, then the widget will not receive notification of failed drops.