From Nexus 2 to Nexus 3, the ability to purge release artifacts older than x days but retain the last y builds was removed. "Number to keep"
If you're only building production release candidates, and never rebuilding to release, using snapshot is difficult. If you're using CI, building on commit to master, then the artifacts/wars start to accumulate. You will eventually need to purge, but retaining some, especially the last one deployed and running, is important so we can promote it from dev to test, or test to prod. Please add this feature back.