How do Approval Rules function in GitLab?

Approval Rules in GitLab are designed to specify the approvals needed for a merge request to be accepted and merged into a project. These rules allow project maintainers to enforce a certain level of code quality and collaboration by requiring designated users or groups to review and approve the changes before they can be merged.

When Approval Rules are implemented, they can ensure that a merge request receives the necessary oversight from team members, which is crucial in maintaining code integrity and complying with organizational policies. By defining who must approve a merge request, teams can manage contributions effectively and reduce the likelihood of errors or regressions in the codebase.

In contrast, the other options refer to different functionalities within GitLab. For instance, branch protection levels focus on controlling access to branches, auto-fetching changes pertains to retrieving updates from remote repositories, and CI/CD configuration parameters relate to continuous integration and delivery processes. Each of these functionalities serves distinct purposes, but only Approval Rules specifically address the approval process for code changes within merge requests.