Gtk.TreeDragSource.prototype.drag_data_delete

function drag_data_delete(path:Gtk.TreePath):Boolean {
    // Gjs wrapper for gtk_tree_drag_source_drag_data_delete()
}

Asks the Gtk.TreeDragSource to delete the row at path, because it was moved somewhere else via drag-and-drop. Returns false if the deletion fails because path no longer exists, or for some model-specific reason. Should robustly handle a path no longer found in the model!