For each repository being processed by the repository.cleanup task, this is the current log message being logged each time a repository is about to be processed:
2019-06-20 01:00:00,033-0400 INFO [quartz-3-thread-11] *SYSTEM org.sonatype.nexus.cleanup.internal.service.CleanupServiceImpl - Deleting components in repository <reponame> using policy <policyname>
Logs are examined retroactively and an administrator may change the cleanup policy settings after the task runs. Looking up the settings of the policy later by name may not be accurate as to what conditions were applied at the time of task run.
The actual cleanup policy settings being applied on that repository should also be logged at INFO level to the repository.cleanup task log just before each repository is processed.