Which of the following describes what regression testing checks for?

Regression testing specifically focuses on identifying unintended side effects that may arise from changes made to the codebase or configuration settings of an application. When new features are introduced or existing features are modified, there is a risk that these alterations can inadvertently disrupt the functionality of previously working features. Regression testing involves re-running previously executed test cases to ensure that the existing functionalities continue to perform as expected after such changes.

This type of testing is crucial for maintaining software quality over time, particularly in environments where changes are frequent. By checking for unintended side effects, regression testing helps to catch potential defects early, thereby ensuring that the software remains stable and reliable for users.

In contrast, testing for new features, performance issues, or compliance with user requirements addresses different aspects of the software development process, and while they are important, they do not align with the primary goal of regression testing.