InventoryConfigurableProductFrontendUi adds info about salable quantity for configurable variations in product page.
This module is a part of the new inventory infrastructure. The Inventory Management overview describes the MSI (Multi-Source Inventory) project in more detail.
This module is installed as part of Magento Open Source. It may be disabled if the Inventory Management UI is provided by a 3rd-party system or if you run a headless version of Magento.
InventoryConfigurableProductFrontendUi module contains several extension points.