To clarify, moderators cannot
hide a revision. That's not what the tool does. What happens is a moderator essentially suggests an edit to the revision and, if approved, the content of that particular revision is completely replaced with the new content. We do have an
indicator in the revision history when a revision has been redacted, which gives the reason for the redaction in a tooltip. It's currently only visible to moderators, though I can't remember if there was any reason not to show it to all users. We may just make that visible to everyone. —
animuson ♦ Feb 7 at 19:12