7 files declare their use of EditableOrderPanePluginBase in Ubercart 8.4

AddressPaneBase.php in uc_order/src/Plugin/Ubercart/OrderPane/AddressPaneBase.php

AdminComments.php in uc_order/src/Plugin/Ubercart/OrderPane/AdminComments.php

CustomerInfo.php in uc_order/src/Plugin/Ubercart/OrderPane/CustomerInfo.php

LineItems.php in uc_order/src/Plugin/Ubercart/OrderPane/LineItems.php

Payment.php in payment/uc_payment/src/Plugin/Ubercart/OrderPane/Payment.php

Products.php in uc_order/src/Plugin/Ubercart/OrderPane/Products.php

Quotes.php in shipping/uc_quote/src/Plugin/Ubercart/OrderPane/Quotes.php