What does enabling the Run all local tests checkbox do during the UAT deployment?

When the option to enable the Run all local tests checkbox is selected during a User Acceptance Testing (UAT) deployment, it triggers all local Apex tests in the Salesforce environment, irrespective of whether the user has chosen to run specific tests or not. This allows for a comprehensive validation of the code being deployed, ensuring that all potential issues are caught before the code is moved to production.

Running all local tests helps maintain quality and stability in the deployment process, as it ensures that all test classes are executed and any failures are reported, providing developers and testers the necessary feedback on the code's performance. This practice is essential for identifying regressions or any unforeseen issues since it tests every piece of functionality covered by Apex tests in the local environment.

If other options suggest different functionalities, such as with regards to limitations on tests or user interactions, they do not accurately represent the behavior of the checkbox in question.