This module helps you find and prevent the deletion of entities that are referenced by other entities. It provides a service to query for references and an optional sub-module to enforce deletion restrictions, thus maintaining data integrity and preventing broken links.
Entity Reference Integrity is a module that allows you to find out which other entities reference a given entity. The base module comes with a service that allows you to query Drupal for this information. If you are a developer you may use this base module simply for the services it provides.
A sub-module "Entity Reference Integrity Enforce" allows you to configure which entity types are "protected" then will attempt to stop that entity from being deleted if any other entities reference it. This is helpful for preserving the integrity of your entity reference fields and stopping dangling references which can cause all sorts of other issues.