11 classes are annotated with CommerceCheckoutPane in Commerce Core 8.2

BillingInformation in modules/checkout/src/Plugin/Commerce/CheckoutPane/BillingInformation.php

Provides the billing information pane.

CheckoutTest in modules/checkout/tests/modules/commerce_checkout_test/src/Plugin/Commerce/CheckoutPane/CheckoutTest.php

Provides a test pane used in test to test the dependency removal.

CompletionMessage in modules/checkout/src/Plugin/Commerce/CheckoutPane/CompletionMessage.php

Provides the completion message pane.

CompletionRegister in modules/checkout/src/Plugin/Commerce/CheckoutPane/CompletionRegister.php

Provides the registration after checkout pane.

ContactInformation in modules/checkout/src/Plugin/Commerce/CheckoutPane/ContactInformation.php

Provides the contact information pane.

CouponRedemption in modules/promotion/src/Plugin/Commerce/CheckoutPane/CouponRedemption.php

Provides the coupon redemption pane.

Login in modules/checkout/src/Plugin/Commerce/CheckoutPane/Login.php

Provides the login pane.

OrderSummary in modules/checkout/src/Plugin/Commerce/CheckoutPane/OrderSummary.php

Provides the Order summary pane.

PaymentInformation in modules/payment/src/Plugin/Commerce/CheckoutPane/PaymentInformation.php

Provides the payment information pane.

PaymentProcess in modules/payment/src/Plugin/Commerce/CheckoutPane/PaymentProcess.php

Provides the payment process pane.

Review in modules/checkout/src/Plugin/Commerce/CheckoutPane/Review.php

Provides the review pane.