It's on the main landing page
https://esta.cbp.dhs.gov/, however what it says is irrelevant really. It says that if you attempt to enter the USA while they are disallowing entry, your ESTA will be cancelled. But you can't get in anyway. It's being misinterpreted that ESTAs are being cancelled automatically. They aren't. However, some people have said that entering Advance Passenger Information on an airline booking may be seen as an attempt to enter the USA. So my instinct as always if you've got a holiday planned is just to sit tight and do nothing until it's cancelled by the operator or restrictions are lifted, unless you want to cancel voluntarily first. But when restrictions are lifted and your holiday is going ahead or you're about to book a new one, do check the validity of your ESTA just in case something has triggered its cancellation. This is my interpretation.