All Abandoned Carts could be viewed on the “Abandoned Carts“ grid
Go to Magento Admin panel - Sales - Abandoned Carts
The “Need Resync” column has two states (Yes/No)
Yes - means that the abandoned cart was just created and needs to sync synced for the first time. But also “Yes“ state means that the previously synchronized abandoned cart has some changes which are not synced yet
No - means that the abandoned cart is synchronized and up to date
Exception
In some cases abandoned cart “Need Resync” column could have “No“ state but is not synchronized: