Do action sheets, share sheets, and document pickers need a popover anchor on the inner display?

Camera, gallery, and PDF choices use UIAlertController style .actionSheet with no popover source. Receipt sharing uses UIActivityViewController, and uploads use UIDocumentPickerViewController; only some set sourceView, and almost none set a real sourceRect. On iPad those presentations need an anchor. On the unfolded Duo display, where the size class is regular, does UIKit still present them as phone sheets, or must every one set sourceView and sourceRect?