It has always only shown that (date, time) for me, even back in A11.
Long press on whatever occupies currently the spot does bring up the “At a Glance” menu for me, even if the search bar is currently showing.
It seems… But I rather think this “At no Glance” widget is, and has always been broken.
Initially (A11) I hoped it would show my upcoming calendar entries – never happened. Weather? No way. Well, it does show the date, in case I go Rip Van Winkle (but in this case it would lack the year…). 