Last modified: 2010-05-15 15:51:58 UTC
When you add a group to $wgRestrictionLevels or a permission to $wgRestrictionTypes, it will show a broken message at the protection screen (<protect-level-foo>) because there's no interface translation message for that group/permission. The software should generate one or assume one is there with default filler text, like "[Group]s only" and "[Permission]".
Fixed in r24733.