PHP 7.3 reaches end of support in December 2021 and Adobe Commerce 2.3.x reaches end of support in April 2022. You may want to consider planning your upgrade now to Adobe Commerce 2.4.x and PHP 7.4.x to help maintain PCI compliance.

Magento_CustomerBalanceGraphQl

The CustomerBalanceGraphQl provides type and resolver information for enabling customers to have a non-monetary balance in store credits associated to their accounts. Store credit can be used by customers for shopping in the store and by the store administrator for making refunds.