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.
Rule
Magento_Rule module provides abstract implementation of rules and rule conditions that are extended by other modules, in particular by: Magento_SalesRule, Magento_CatalogRule, etc…