Upgrade Compatibility Tool offers a possibility to compare a client's Adobe Commerce installation with a clean vanilla installation to see if the core code has any modifications made to implement a new feature or customization.
This check might also be helpful during presales, consulting engagements like a Health Check to understand how healthy the codebase is.
Steps for the check
Install UCT
composer create-project magento/upgrade-compatibility-tool uct --repository https://repo.magento.com
Install vanilla Magento
Note: "2.4.4-p2" is used as an example
composer create-project --repository-url=https://repo.magento.com/ magento/project-enterprise-edition=2.4.4-p2 magento-2.4.4-p2
Make a core code changed check
bin/uct core:code:changes <client_magento_dir> <vanilla_magento_dir>