Which component is essential for managing permission assignments during deployment?

Managing permission assignments during deployment is crucial to ensure that users have the necessary access to data and functionality within the application once new features or configurations are deployed. Permission sets are specifically designed to grant additional permissions to users without changing their profiles. This means that when a deployment occurs, using permission sets allows organizations to assign the required permissions to users in a way that can be easily managed and adjusted as needed, enhancing flexibility and security.

Integration endpoints, deployment tasks, and Apex steps, while important in the deployment process, do not directly relate to the management of user permissions. Integration endpoints focus on connecting different systems, deployment tasks involve the specific actions taken during deployments, and Apex steps pertain to executing custom code as part of a deployment. Thus, permission sets stand out as the essential component for managing who has access to what during the deployment lifecycle, making them the correct choice for this question.