Map Viewer Classic had it, the not so new now Map Viewer doesn't - is there any way to format dates in AGOL to follow the rest of World standard, non-US, date formats of dd-mm-yyyy or yyyy-mm-dd? Is it in for a planned AGOL update?
You'd think since dd-mm-yyyy was in Classic, it would have been brought through to the new viewer.
If you go to your User Profile, you can change your locale to something different from English-US. For instance, you can use English - Great Britain or English Australia. In that case, Map Viewer will display all dates as dd-mm-yyyy