6 files declare their use of CartManagerInterface in Ubercart 8.4

CartBlock.php in uc_cart/src/Plugin/Block/CartBlock.php

CartController.php in uc_cart/src/Controller/CartController.php

CartLinksForm.php in uc_cart_links/src/Form/CartLinksForm.php

CheckoutController.php in uc_cart/src/Controller/CheckoutController.php

EmptyCartForm.php in uc_cart/src/Form/EmptyCartForm.php

TwoCheckoutController.php in payment/uc_2checkout/src/Controller/TwoCheckoutController.php